# Managing Groups and Teams/Psychological Profiling

## Introduction

Psychological profiling in team building can be a very useful tool in
distinguishing personalities, traits, characteristics, strengths and
weaknesses of each team member. From the beginning of time, people have
had to work together and because no two people are alike, not even
twins, the mind and overall psychological makeup or personality of a
person can be an important aspect in building effective and productive
teams.

In the early 19th century, when astronomers timed the passage of stars
overhead, they noticed they all came up with different results. They
took these differences and made an analysis of what they called the
\"personality\" of the eye. Even as far back as the mid-1800\'s,
distinguished scholars were championing the whole person as a unit of
study. From that point forward, individual psychologists began to
conceptualize personality and behavior differently.

Psychological profiling is a useful tool in the selection of a team,
team alignment, personal development, coaching, and the overall team
development. A team can certainly be formed without psychological
profiling; however, with the power of knowing the personality and mind
of each team member better, it gives the team a head start in meshing
and forming the most effective team possible.

## What is Psychological Profiling?

Psychological profiling is the analysis of an individual or teams
behavior and psychological characteristics, used especially to identify
and explain the makeup of that person or the team in question. If the
organization or team can better understand the makeup, behavior, and
characteristics of the members of that team, it is more likely that
those paired up will behave more congenial and have more overall
cohesion within the group.

Sir Francis Galton may properly be called the first practitioner of
psychological testing. It has been said that he originated mental tests,
and assumed that intelligence could be measured in terms of a person\'s
level of sensory capacity-the higher the intelligence, the higher the
level of sensory discrimination. Galton also began a long line of
research on mental imagery, much of which included the first extensive
use of the psychological questionnaire. Sigmund Freud, Carl Jung, James
Cattell, B.F. Skinner and other great minds can also be much accredited
for bringing psychological profiling to not only the individual, but to
the groups or teams within organizations.

Carl Jung\'s theory of psychological types says each person is \"wired\"
with different tendencies and preferences. Some of us are extraverted
while others are introverted, some are \"thinkers\" while others are
\"feelers\", and so on. Carl Jung also once said, "Personality is the
supreme realization of the innate idiosyncrasy of a living being. It is
an act of high courage flung in the face of life, the absolute
affirmation of all that constitutes the individual, the most successful
adaptation to the universal condition of existence coupled with the
greatest possible freedom for self-determination." In order for the team
to understand the individual, the individual must also understand
themselves.

Personality is often said to be the major makeup of an individual person
or team's make-up. A contemporary definition for personality is offered
by Carver and Scheier (Professors of Psychology): "Personality is a
dynamic organization, inside the person, of psychophysical systems that
create a person's characteristic patterns of behavior, thoughts, and
feelings." Important aspects of the psychological or personality makeup
may be:

-   Dynamic Organization: suggests ongoing readjustments, adaptation to
    experience, continual upgrading and maintaining Personality doesn't
    just lie there. It has process and it's organized.
-   Inside the Person: suggests internal storage of patterns, supporting
    the notion that personality influences behaviors, etc.
-   Psychophysical systems: suggests that the physical is also involved
    in 'who we are'
-   Characteristic Patterns: implies that consistency/continuity which
    are uniquely identifying of an individual
-   Behavior, Thoughts, and Feelings: indicates that personality
    includes a wide range of psychological experience/manifestation:
    that personality is displayed in MANY ways.

Carver & Scheier also suggest that the word personality "conveys a sense
of consistency, internal causality, and personal distinctiveness". This
issue of "personal distinctiveness" is very important. There are certain
universal characteristics of the human race and particular features of
individuals. We all for example experience stress and the elevated
pressure that goes with it. The real key is this though - Every one of
us is unique too. That is why using psychological profiling can point
out much of those unique points and point the team in the right
direction to play on those unique points, while also meshing with the
similar characteristics.

## Types of Psychological Profiling

There are many types or ways an organization can perform psychological
profiling in building and sustaining teams. Actual tests or
questionnaires can be performed -- possibly the number one way most
people may think of psychological profiling. However, there are other
ways. Psychological Profiles also known as Personality profiles can be
deduced from any public information such as demographic data, internet
search, media, opinions, blogs, social networking services, wikis,
newsgroups, words, voice, pictures, videos, biological features,
physical features, body language, forums, message boards including other
methods such as statistical comparisons with peer groups.

Factors such as how people create various usernames, emails, IM Names,
the way people write, the style and method of writing, the words they
use, their pictures, videos, voice, biological features, physical
features, body language, their comments etc also have relevance. This
can also help to understand and estimate behavior in different social
and team situations.

Relevancy of a personality profile also known as psychological profile
is proportional to the accuracy of the background information you
provide. The fundamental point of profiling is comparing a subject\'s
behavior with the behavior of others in similar circumstances who have
been studied in the past. The key to good profiling is in deducing what
background effects what trait and identifying patterns. Often times what
most people commonly consider to be irrelevant pieces of information
could be very relevant for any trait. It is also possible that people
have a certain trait but do not act upon it due to external
circumstances that make it very difficult for them to act in accordance
with their natural trait. In these situations when the external
circumstances are removed people revert to their natural trait.

There are no traits that are all bad or all good. Good or bad is very
relative and defined according to the society one lives in or the
circumstances. Certain traits in certain situations would be extremely
desirable and those same traits in a different situation could be
extremely undesirable. And even within the same society, concepts of
good or bad may change over time, particularly if influenced by evolving
societal values or expectations.

Often times people\'s own perceptions about their behavior, thoughts or
functioning are biased by their own ideal image and experiences.
Objective observers, on the other hand can provide a more unbiased
assessment of these behaviors. To you your own traits, may seem
perfectly normal, typical or not typical. Yet to those around you, they
may seem typical, odd or abnormal. Normal is often defined by what\'s
statistically average. Most people fall in the middle ground, the
average, while others fall to one extreme or the other. And what is
normal also changes over time particularly when influenced by evolving
societal values or expectations.

Although there are a number of ways psychological profiling may be
administered to the individual or the team as a whole, below are some
major tools used by many organizations to understand the team building
process better. It is best to analyze the particular industry and
business that is in need of team building and decide upon the best tool
available for that organization. One may find that not only one tool is
sufficient, but may need multiple tools to understand fully and reach
the goals of team building that are needed for ultimate success. The
options available specifically for teams are bolded:

  Personal Competence                                              Social Competence
  ---------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Adversity Quotient (Paul Stolz, 2000)                            Similar to resilience and hardiness, the Adversity Quotient has been proposed as an indicator of capacity to withstand and thrive on challenging circumstances **specifically related to business and the workplace.**
  Enneagram (Google search)                                        Personality tool based on 9 personality types. Developed with a more deeply historical and spiritual orientation than most other similar questionnaires by some leading humanistic psychologists, including Gurdjieff, Ichazo, and Naranjo. The types relate to the major roles that people seem to adopt and play in society. There is no definitive Enneagram questionnaire - various free and commercial versions are available.
  DiSC Management Strategies (Corexel)                             Commonly used tool and associated training program for providing feedback and improving on people\'s self-management and **team management in workplace settings**.
  Herrmann Brain Dominance Instrument (Herrmann, 1970\'s)          The HBDI 120-item self-report diagnostic tool which provides thinking styles profiling based on left-right hemisphere preferences and cognitive vs. limbic thinking preferences. Can also be used for **team profiling, building, and analysis**.
  Human Synergistics (Human Synergistics International, 1970\'s)   A thinking style / personality profiling and feedback system, plus training program, which can be completed on an individual, team and organization level to assess strengths and areas for improvement/change in individual effectiveness.
  Keirsey Temperament Sorter                                       Similar to the MBTI, identifies 16 personality sub-types, based on dichotomous ratings on 4 main personality factors which are derived from the psychological work of Carl Jung.
  Myers-Briggs Type Indicator                                      The MBTI is the most widely used personality assessment questionnaire, **particularly in workplace training**. The MBTI identifies people as being one of 16 overall types, based on dichotomous ratings on 4 main personality factors.
  Team Management Systems (Margerison & McCann, 1980\'s)           **Profiles the kinds of kind of roles people prefer to play in groups and teams**. Provides individual and **team-levels** of analysis. **Used to help improve quality of team performance.**
  360-Degree Feedback                                              System for gathering feedback from others about personality and work styles which makes particular use of combining observer ratings and comparing with self-ratings.

These instruments are commonly used and recommended as comprehensive
personality and team profiling tools. These tools are often used by
organizational consultants, managers, individual team members, and
workplace trainers to help facilitate understanding of:

-   personal strengths and weaknesses
-   other team members\' strengths and weaknesses
-   a team\'s overall strengths and weaknesses
-   an organization\'s overall strengths and weaknesses

## Conclusion

As we have discussed in this section, psychological profiling can be a
very important and useful tool in team building and maintaining
effective groups. With psychological profiling being the analysis of an
individual or teams behavior and psychological characteristics, used
especially to identify and explain the makeup of that person or the team
in question, one may better understand the dynamics or make-up of each
individual and overall team better.

It is also imperative to remember that there are many types of
psychological profiling as discussed in this section, ranging from
search, media, opinions, blogs, social networking services, wikis,
newsgroups, words and so forth, to actual testing, questionnaires, etc.
Testing may include such options as: DISC Management Strategies, Team
Management Systems, Myers-Briggs Type Indicator, and so on. These tools
help to not only understand the individual and the "map" they are
working on, but also how these individuals will affect the team and the
overall potential of cohesiveness, productivity, and possible
effectiveness. Understanding the benefits and drawbacks of psychological
testing, knowing what tool to use and when to use it, can be a major
assistance to any organization and or groups/teams. Recognize the
audience being profiled and determine what is best for the purpose the
organization is looking to achieve.

## ***References***

Carver, C. S., & Scheier, M. F. (2000). Perspectives on personality (4th
ed.) Boston: Allyn and Bacon.

Burger, J. M. (1993). Personality (3rd ed.) Pacific Grove, CA:
Brooks/Cole.

Ridley, M (1999). Genome: The autobiography of a species in 23 chapters.
London: Fourth Estate.

Schultz, D., & Schultz, S.E. (1994). Theories of personality (5th ed.)
Pacific Grove, CA: Brooks/Cole.

Website References:

<http://www.minddata.com/history2.asp>

<http://www.abika.com/help/Accuracy.htm>

<http://wilderdom.com/tools/ToolsPersonality.html>


# Managing Groups and Teams/Team Building Activities

## Team Building Activities

**Introduction**

Team building activities are important for a number of reasons. Everyone
participating will enjoy the benefits including the work force,
management, customers, up to the stockholders. Team building can keep
employees motivated and enthusiastic about every phase of their job. It
may not be easy to always get the group or team members excited about
doing an activity, but if implemented well, it can bring a sense of
purpose and unity unlike anything else. Once you get everyone to
understand the importance of team-building, the program has a better
chance of being accepted.

Team-building activities help people understand the importance of
working together. A company is more productive when everyone works
together for a common goal, without factions or other divisive elements.
Along with understanding the importance of working together, below are
the benefits that can be reaped by effective team building activities,
namely:

**Establish Rapport**

When an organization utilizes team building activities it helps
employees to establish rapport with each other. This helps employee's
work together in an amicable environment.

**More Productive**

Team building activities help employees understand that they are much
more productive working as a cohesive unit trying to accomplish the same
goals and objectives. More work is accomplished by a team than one
person could ever hope to accomplish alone.

**Cut Costs**

Employees that participate in team building activities are more
energetic, enthusiastic and are absent from work less often. This
reduces costs for the company across the board.

**Quality Ideas**

When there are team building activities employees are more likely to
submit ideas that ultimately help the organization function more
efficiently and could save money. Ideas can help a company capture
market share, develop people and save time.

**Brainstorming**

A team that comes together can accomplish just about any objective when
they cooperate to brainstorm different scenarios aimed at achieving
goals.

**Team Building Activity Examples and Starters:**

Activities that allow team members to work together in a scenario
outside of their normal group environment can be an extremely effective
way to build cohesion and unity. Some are simple and some can be
complex. Some are short, and others can be very involved!

Every team activity requires a small amount of planning, a few supplies,
and an effective activity planner. Here are some examples of some fun
and simple activity ideas!

***EGG DROP ACTIVITY***

Teams work to build a holding container that will protect an egg when
dropped from two or three stories high.

-   Engaging and very messy small group activity (4 or 5) as part of
    larger group (e.g., 20 up to 100)
-   Can be run as a competition between teams
-   Task is to build a single egg package that can sustain a fall of
    whatever height you decide
-   Can be used to highlight any almost aspect of teamwork or leadership
-   Lends itself to production line or project management metaphors

*Materials* (Provide the materials for each team to use, or allow them
to gather their own materials.)

A suggestion of useable supplies:

Drinking Straws

Tape

Towel

Rubber band

Masking tape

Egg

*Timing*

\~30-45 minutes to build package

\~15-30 minutes for Great Egg Drop

\~15-45 minutes cleanup & debrief

***MULTI-WAY TUG-OF-WAR***

Teams work to pull the other teams across a center line using guile and
strategy.

-   Fun, finale-type activity. Physically exhausting and emotionally
    climaxing!
-   Works for kids through to corporate programs. Ideal for adolescents
    and possibly youth at risk. Especially with older adults, be careful
    with this activity, especially if they are unfit or if overexertion
    is contraindicated (e.g., heart problems).
-   Use for any size groups, indoor or outdoor. Ideal is large group
    outdoors. Pick a soft location e.g., grass/beach.
-   In traditional 1 on 1 tug-of-war it is mostly strength that wins,
    with a few tactics.
-   In multi-way tug-of-war it is mostly tactics that wins, with some
    strength.
-   Lay out the ropes, etc. as shown in diagram below.
-   Participants should prepare appropriately e.g., watches and hand
    jewellery off.
-   Divide into groups and make sure the groups appear to be of similar
    strength.
-   Brief group on normal tug-of-war safety rules, basically:
    -   no wrapping or tying rope around anyone or anything - only hold
        rope with hands
    -   watch out for rope burn on hands - let go if rope is moving
        through hands
    -   watch out for rope burn on body - let go if you lose footing
-   First command from the Tug-of-War master is \"take the strain\".
    This is only to take up the slack, that\'s all. The Tug-of-War
    master makes sure the centre ring is stable and centered. This needs
    strong leadership because teams are always keen to add extra strain!
-   Second command is \"Go!!\"
-   Teams attempt to pull the center ring or knot over their finish
    line. This can rarely be achieved by strength alone and instead will
    require guile. Teams can swivel to cooperate / compete with other
    teams, then switch directions, etc.
-   Conduct several rounds. Continue, say, until one team earns 3
    victories and the Tug-of-War title.
-   Allow teams plenty of time to physically recover and debrief/plan
    after each round.
-   Team building groups may wish to discuss what the secrets to success
    were in this activity - and whether these lessons apply elsewhere.

*Materials*

Make your own 4 way tug of war with several good quality ropes each
\~60ft+ with attachment e.g., via knots, splicing or ring/karabiners

*Timing*

\~30-60 minutes

**References**

For descriptions on these and other great ideas for activites, see:

<http://wilderdom.com/games/InitiativeGames.html>

<http://www.teambuildingactivities.net/>

<http://www.ehow.com/facts_5407800_importance-team-building-activities.html>


# Managing Groups and Teams/Glossary

1.  **Action oriented.** This is the tendency to act and encourage
    others to perform. It is a intended effort to make something happen.
2.  **Accountability.** Accountability is entailed by responsibility.
    Anyone who is responsible is thereby accountable. To be responsible
    is to accept judgments, acts and omissions (refusals or failures to
    act) as one\'s own burden where appropriate, and in whole or in
    part. Accountability is a state of responsiveness. The readiness or
    preparedness to give an explanation or justification to relevant
    others (stakeholders) for one\'s judgments, intentions, acts and
    omissions when appropriately called upon to do so.
3.  **Altruism.** The satisfaction that comes from knowing that your
    responsibilities and work have a beneficial affect on others.
4.  **Ambivert.** One who is not strongly inclined towards the
    characteristics of an extrovert or introvert. Rather, an ambivert
    tends to transition between the two personality types depending on
    the setting at hand. In groups and teams an ambivert may assert
    himself as a leader or vocal group participant or simply take a more
    quiet or reserved role.
5.  **Autonomy.** One who values freedom in the work place and dislikes
    \"micromanagment\".
6.  **Belligerent.** When a person is constantly involved in conflict
    which they have provoked or voluntarily entered.
7.  **Belittle.** Use to make someone or something less important.
8.  **Collaboration.** The willing exchange of diverse and varying
    ideas, visions, and perspectives with the objective of creating a
    unique and dynamic idea to better the organization while working
    together.
9.  **Competency Trap.** Doing the thing we knew worked once, even
    though it isn\'t working now.
10. **Confirmation Trap.** A confirmation trap is the tendency to look
    for additional information that conforms to our understanding of a
    situation rather than seeking balanced and unbiased evidence that
    may be disconfirming.
11. **Conformity.** is the degree to which members of a group will
    change their behavior, views and attitudes to fit the views of the
    group. Sometimes conformity is distinguished by type: compliance,
    conforming only publicly, but keeping one\'s own views in private;
    identification, conforming while a group member, publicly and
    privately, but not after leaving the group; and internalization,
    conforming publicly and privately, during and after group
    membership. Sociologists believe that compliance is conformity that
    is usually a result of a direct order while internalization is
    conformity that comes from one\'s total and utter belief in one\'s
    act.
12. **Consensus with qualification.** When every member of a team
    discuss a problem or idea and after certain time can\'t have an
    agreedment and the final decision is make by a CEO involved.
13. **Constructive Feedback.** Communication which alerts an individual
    to an area in which his/her performance could improve. Constructive
    feedback is not criticism; it is descriptive and should always be
    directed to the action, not the person.
14. **Core Competency.** This is working knowledge. It is comprised of
    our experience to do the job and having the essential
    problem-solving skills needed to overcome obstacles.
15. **Counterattack.** When we feel that we need to be defensive and
    fight about something that we believe is important to us.
16. **Convergent thinking.** Thought process often adopted by groups in
    which the group brings together similar information focused on
    finding a single best answer to bring closure to and resulting in
    feelings of security about a question, discussion or project.
    Convergent thinking is characterized by the need or intent to find
    one solution or answer to a problem. In other words, the group
    \"converges\" on an answer.
17. **Cross Functional Team.** A cross-functional team consists of a
    group of people working toward a common goal and made of people with
    different functional expertise. It could include people from
    finance, marketing, operations, and human resources departments.
    Typically it also includes employees from all levels of an
    organization. Members may also come from outside an organization (in
    particular, from suppliers, key customers, or consultants).
18. **Cross-functional teams.** It is the team that has the mission to
    work on specific problem, issue or task with the goal of improve
    production.
19. **Culture.** Culture refers to the standards of social interaction,
    values, and beliefs from a given group of people. Cultural issues
    can affect team interactions through different understandings of
    communication, family, and can appear to be an excuse for
    preferential treatment.
20. **Divergent thinking.** Divergent thinking is characterized by the
    production of as many ideas as possible, avoiding repetition or
    convergence.
21. **Diversity.** Team Diversity is the uniqueness of each individual
    on a team. This should not only include the usual diverse selections
    such as religion, sex, age, and race, but also additional unique
    personality characteristics such as introverts and extroverts,
    liberals and conservatives, etc.
22. **Dud-Person:** A person on the team
    who does not have the skills they claimed to have to get on the
    team, or that their manager thought they had when they were assigned
    to the team.
23. **Emotionally Tone-Deaf.** Inability to 'read' body language signals
    in others. Inability to understand how other's emotions affect their
    actions/behaviors.
24. **Empire Builders.** Those to believe that the team that has more
    members is the one that will win.
25. **Empowered Team** It is the team that has the rights to plan and
    put in place any improvements to their process.
26. **Entrenched.** Something well establish. Not for changes.
27. Extrovert. Extroverts tend to be
    energetic, enthusiastic, action-oriented, talkative, assertive,
    gregarious and unreserved. Therefore, an extroverted person is
    likely to enjoy time spent with people and find less reward in time
    spent alone. While extraversion is associated with high levels of
    warmth, and also with enjoyment of thrills and strong sensations, it
    is common also for people to have divergent levels of extraversion
    at this micro or \"facet\" level of the trait - for instance,
    preferring moderate group-sizes, but relishing excitement. They view
    team meetings as productive and energizing. A venue for essential
    thought provoking discussions and a place to surcease any problems
    that may arise.
28. **Facilitator.** A person whose job it is to make sure that meetings
    run well and achieve the goal they are seeking.
29. **Feedback.** Communication to a person or a team of people
    regarding the effect their behavior is having on another person, the
    organization, the customer, or the team.
30. **Group.** A group is a collection of individuals that are linked by
    some associational characteristic(s). In organizations, groups can
    include departments (Accounting, Marketing, etc.) as well as
    temporary sets of individuals (task forces, cross-department groups,
    etc.)
31. **Group Contract.** A formal written contract established by a group
    to eliminate confusion and set a standard for the group\'s
    expectations, individual responsibilities, forms of communication,
    and methods of discipline
32. Group Polarization. A group
    taking on the ideas of a single group member, i.e., one liberal
    talking, soon the whole group is liberal.
33. **Group Potency.** The spiritual energy of a team. Often referred to
    the team's ability to believe in themselves.
34. **Group success.** Success in groups is hard to define. The most
    obvious and commonly used measure of success is performance in the
    task (e.g., productivity). In addition, however, others (notably
    Hackman, 1986) have suggested the need to incorporate additional
    dimensions. Hackman suggests two dimensions that must be accounted
    for, the ability of group members to work together again (viability)
    and the growth of individuals participating in the team (learning).
    The ability of group members to work together again attempts to show
    that, even if a group performs its task well, it is not successful
    if the relationships between members are destroyed. Similarly,
    unless the individual growth objectives of group members are met
    through their participation in a group, the group cannot be
    considered a complete success. Although this expansion of notions of
    group success is valuable, the research literature on groups does
    not have a uniform or universal understanding of what constitutes
    group success.
35. **Groupthink.** Process where members of a group start thinking
    alike and there are less individual ideas and creativity.
36. **Guided Experience.** Process by which agencies can tap into the
    knowledge of their employees by using a coach to expedite the
    process and create a database of shared insights and knowledge.
37. **Halo Effect.** The halo effect is our tendency to assume that if
    one is excellent in some dimensions that will be excel in others
    even though they are not related in nature.
38. **Heterogeneous Group.** The people who join this kind of group
    usually have differente knowdlege, education, values, etc. This
    group usually are very competitive.
39. **Homogeneous Group.** The people who join this group have similar
    experience, feelings, values, etc. This group usually are very
    supportive.
40. **Homosocial reproduction.** The tendency of workplaces to promote
    according to social identification and individuals moving in the
    \"right\" social circles. For example, in a male-oriented workplace,
    corporate executives and managers may provide greater weight to the
    activities and interests of other men, thereby favoring them
    (sometimes unconsciously), giving them greater opportunity and
    greater access to promotions.
41. **Infrastructure.** The underlying base or foundation for the group
    or team. This could take the form of the various roles within the
    team/group or the policies and procedures that exist for the team.
42. **Integration.** The combining efforts of various departments,
    personnel, and social classes to promote diversity, collaboration
    and education in a safe and productive environment with the purpose
    of achieving a higher understanding and knowledge of any particular
    problem or solution.
43. **Introvert.** One who\'s thoughts and interests are directed
    inwardly rather than outwardly toward others. In groups and teams
    introverts may be inclined to take a back seat role rather than
    assert their opinions or views to the other group members.
44. **Interface.** A point where certain groups or teams can interact.
    This could be in the form of a certain person that acts as a liaison
    for multiple groups, or it could be a medium, such as teleconference
    or some other technology.
45. In-group. (from Wikipedia) In sociology, an
    ingroup is a social group towards which an individual feels loyalty
    and respect, usually due to membership in the group. This loyalty
    often manifests itself as an ingroup bias. Commonly encountered
    ingroups include family members, people of the same race or
    religion, and so on. Research demonstrates that people often
    privilege ingroup members over outgroup members even when the
    ingroup has no actual social standing; for instance, a group of
    people with the same last digit in their social security number.
46. **Interdependence.** A dynamic of being mutually responsible to and
    dependent on others. Each unique action is key to overall system
    success.
47. **Interpersonal Reflex.** The social phenomenon in which one
    person\'s behavior (smiling, complaining, goofing off) can cause
    others to unconsciously behave similarly. Also called the \"Dyadic
    Effect,\" the \"Norm of Reciprocity,\" and the \"Lock-in Effect.\"
    (Team 8)
48. Leadership. Skill that somebody has to
    drive a group or a team. Be the leader mean that other members of
    the team come to you with questions or because they need somebody to
    help them when they have a task assigned. Usually is the person with
    knowdlege and experience, but some people has a innate leadership.
49. **Management.** The close and steering direction of a group, often
    has a more negative connotation than leadership.
50. **Marginalize**. to place in a position of marginal importance,
    influence, or power
51. **Mentoring.** Mentoring is a supportive learning relationship
    between a caring individual who shares his/her knowledge, experience
    and wisdom with another individual who his willing and ready to
    benefit from this exchange to enrich his/her professional journey.
52. **Meritocrats.** Individuals that feel emotion, but do not believe
    that emotion should play a part in making decisions. These people
    have problems functioning because they do not understand the
    motivations that drive other's decision making processes.
53. **Mindguarding.** Symptom of groupthink in which an individual or
    individuals in a group appoint themselves to the role of protecting
    the group from adverse information or disturbing ideas that might
    threaten group complacency.
54. **Motivate.** To provide someone with an incentive to do something;
    proper incentives should outweigh actions required to achieve
    incentives, although it is not required.
55. **Newcomer.** A newcomer is an individual who has recently joined
    the group, a newby. A newcomer joins the group for a variety of
    reasons, including the need of the group for greater work capacity
    (in volume, skill, or knowledge) and the need of the individual to
    accomplish his or her own goals.
56. **Openness.** Be able to discuss an issue, a problem or situation
    with a peer, relative or superior and be honest and open about what
    we think and our feelings.
57. **Organizational design.** It is the way a office, group or company
    is structured and presented to all the employees and public in
    general. Employees will know to what area they belong and to who
    they have to report.
58. **Organizational politics.** The desire of those within an
    organization to further their own interests rather than achieving a
    collective goal.
59. Out-group "wikilink") (from Wikipedia) In
    sociology, an outgroup is a social group towards which an individual
    feels contempt, opposition, or a desire to compete. Members of
    outgroups may be subject to outgroup homogeneity biases, and
    generally people tend to privilege ingroup members over outgroup
    members in many situations.
60. **Passive Conspiracy.**A way of avoiding confrontation by
    dysfunction. It is an evolved group norm and results in an agreement
    to accept the condition rather than deal with it openly.
61. **Peacekeeper.** Person who avoids conflict at all cost, to the
    point of detrimental behavior.
62. **Peacemaker.** Recognize conflict; attempt to resolve rather than
    avoid.
63. **Personal agendas.** A dysfunctional group dynamic that undermines
    the group objectives. Occur when the natural process of jockeying
    for a position of status within the group progresses into individual
    members of the group becoming overly preoccupied with personal
    concerns and position within the group.
64. **Positive Feedback.** Communication which involves telling someone
    about their good performance. Make this feedback timely, specific,
    and frequent.
65. **Primacy.** Primacy is the tendency to form judgements and images
    of people based solely on the first impression and interaction.
66. **Process Loss.**
67. **Projection.** Process where we see our own psychology reflected in
    others. You assume that others have the same motivations and
    responses as you do.
68. **Project Team.** Are individuals working together who share a
    common goal that is achieved through the application of various
    combined skills. Common goals are essential to success, but the team
    unity should not be taken for granted.
69. **Race.**Race is defined as a group of people, often of a common
    geographic origin, that share genetically transmitted physical
    characteristics. Racism is the belief that these inherited
    characteristics affect an individual's behavior or abilities.
70. Risky Shift A special case of group
    polarization, also rooted in groupthink, in which group discussions
    lead members to adjust their positions to a more cautious or more
    risky position from the one they held in advance of the discussion.
    For instance, in a group of individuals that are cautious, a group
    decision is likely to be even more cautious than the individual
    positions would suggest once risky shift takes place.
71. **Self-corrective.** This is a term used in relationships in which
    all parties involved commit to making changes that will improve the
    relationship.
72. **Self-directed teams** It is the team that is responsible for
    supervisory responsibilities.
73. **Self-motivated individual.** An person who requires little
    external motivation from the team leader.
74. **Self-Serving Bias.** When people are more likely to claim
    responsibility for successes than failures. Manifests itself as a
    tendency for people to evaluate ambiguous information in a way
    beneficial to their interests. Self-serving bias also results in a
    statistical bias resulting from people thinking that they perform
    better than average in areas important to their self esteem.3
75. **Social biases.** Social biases are "shortcuts" that we, as
    individuals, use to make sense of the world. As people, we make
    systematic mistakes in the way we see the world. Social Psychology
    and other disciplines have worked to identify those biases and to
    understand how they can affect our behavior in social situations.
    Social biases are always related to the way in which we see and/or
    understand other people and their actions. They are broad, involving
    everything from how we form and use first impressions of others, to
    how we construct histories and motivations for the actions of
    others.
76. **Social Loafing.**The tendency of individual group members to
    reduce their work effort as groups increase in size as displayed by
    the inclination to \"goof off\" when performance is needed in a
    group, miss meetings, show up late, or fail to start or complete
    individual tasks.
77. **Social processes.** A social process is present in any situation
    where an individual is relating him- or herself to others. Social
    cognition, for instance, is present when an individual makes
    decisions on the basis of thinking of social categories or social
    interactions. Another type of social process is social interaction,
    where an individual actively interacts with one or more other
    individuals. Conversations and meetings are both examples of social
    interactions.
78. **Soft Skills.** A set of skills that influence how we interact with
    each other. It includes such abilities as effective communication,
    creativity, analytical thinking, diplomacy, flexibility,
    change-readiness, and problem solving, leadership, team building,
    and listening skills.
79. **Stagnate.** When something stops improving. Also used when a plan
    is not developing anymore.
80. Stereotype (from Wikipedia). We build
    stereotypes to simplify the world by putting people into categories,
    and then fitting individuals into the stereotype of that category.
    For example, if doctors are all X, and you are a doctor, then you
    must also be X. Stereotypes are beliefs that all members of specific
    groups share similar traits and are likely to behave in the same
    way. In most cases, the characteristics described by a stereotype
    tend to be negative (e.g., all engineers are eggheads who can't
    relate to people), although occasionally stereotypes involve
    positive attributes (e.g., accountants are very careful and
    precise). The problem is that individuals never conform to an exact
    stereotype, given that individual differences outweigh similarities
    with others in a group.
81. **Strategy.** A plan of action resulting from strategy or intended
    to accomplish a specific goal. The art or skill of using stratagems
    in endeavors such as politics and business.
82. **Superordinate Goal.** Goal for the team, that takes precedence
    over each team member's individual goal.
83. **Supportive.** Used specially in teams. Be a good member of the
    team, help each other and always looking for ways to help other
    members of the team to succeed.
84. **Synergy.**
85. **Tangled.** When a situation, problem or issue is confusing or
    complicated.
86. **Team Contract.** A team document that clearly and specifically
    outlines the expectations for performance, productivity, quality and
    quantity of work, and efficiency for each team member.
87. Team (from Wikipedia)
88. **teamwork** When two or more people get together to achieve a
    specific goal. The succeed of the team is responsibility of all
    members.
89. **Veteran.** A veteran in a group is an individual who has longer
    tenure within the group, who has a history with other members in the
    group context.
90. Virtual Team (from Wikipedia). A
    Virtual Team is a group of individuals who work across time, space,
    and organizational boundaries with links strengthened by webs of
    communication technology. Like other teams, they have complementary
    skills and are committed to a common purpose, have interdependent
    performance goals, and share an approach to work for which they hold
    themselves mutually accountable. Geographically dispersed teams
    allow organizations to hire and retain the best people regardless of
    location.

**References**

1.      Foland, Jeremy. May 4, 2006. MGP-295.1 Managing Teams and
    Technology. UC Davis, Graduate School of Management.

2.      Okhuysen, G.A., in \"A desperate attempt at referencing,\" *Journal
    of Unmemorable Quotes*, 2006.


# Managing Groups and Teams/Question Page

This book is organized around questions related to topics on the
management of groups and teams. In this page, we want to list questions
that would be relevant to the topic, to eventually formulate answers for
them and incorporate them into the main body of the book.

Feel free to add questions to this list, and to reorganize them or group
them together if you see common threads. As the questions are refined,
they will be easier to answer.

## For Future Study

### Commitment

-   How can different levels of commitment be avoided during the
    selection process?
-   Is it necessary for all team members to be equally committed to a
    project?
-   If large disparities exist, how can these be addressed?
-   How should the team deal with members who are not committed?
-   How should the team deal with members who have taken on more than
    their share?

### Selection

-   How can teams change membership composition without disrupting the
    remaining members?
-   Are some personalities simply unsuited for teamwork?

### Effective Use of Time and Resources

-   What should the team and its members do when the tasks seem to be a
    waste of time?
-   What should the team do when its mission and goals are ambiguous?
-   How can the team choose an effective course of action when there are
    varying opinions on what to do?
-   What can team members do when meetings are ineffective or
    confrontational?
-   When should team members be flexible and when should they stick to
    their guns?
-   How can team members choose effective task orders, assignments,
    etc.?
-   What are some hallmarks of ineffective plans and how can these be
    avoided?
-   What makes for effective time management?
-   How can delegation be used effectively?

### Team Culture

-   How is team culture established?
-   How can remote and isolated team members become acculturated?
-   Is/should culture be established at the outset? Can culture be
    changed later on?

### Social Graces

-   What are the key social graces all team members should have?
-   What social criteria are important when selecting members?
-   What can teams do when members lack proper social graces?

### Knowledge Differences Among Team Members

-   How can teams deal with members who have different technical
    aptitudes?
-   What are the conflicting dynamics between older members who have
    experience, but may lack the technical knowledge of younger members?
-   Do varying levels of technical knowledge result in power
    inequalities?
-   How can members communicate effectively in light of knowledge
    asymmetries?
-   What can be done to avoid communication breakdowns?

### Leadership

-   What should team members do if the leaders motivations are political
    and do not have the teams best interest at heart?
-   Should team members ask a leader to step down if they have lost
    confidence in him or her?
-   What should a leader do if team members are losing confidence in him
    or her?
-   How can leaders encourage healthy communication?
-   What should people do when their role changes from team member to
    team leader?
-   How can leaders remain objective? Should leaders always be
    objective?
-   Do different organizations require different leadership styles---eg.
    government, military, academia etc.?
-   In a leaderless team, how can one effectively assume the role of the
    leader?

### Diversity in Teams

-   What cultural differences should team members be aware of?
-   How can team members ensure that cultural or political differences
    to not inhibit performance?


# Basic Physics of Nuclear Medicine/Atomic & Nuclear Structure

![](Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.png "Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.png"){width="150"}

You will have encountered much of what we will cover here in your high
school physics. We are going to review this material again below so as
to set the context for subsequent chapters. This chapter will also
provide you with an opportunity to check your understanding of this
topic.

The chapter covers atomic structure, nuclear structure, the
classification of nuclei, binding energy and nuclear stability.

## Atomic Structure

The atom is considered to be the basic building
block of all matter. Simple atomic theory tells us that it consists of
two components: a nucleus surrounded by
an electron cloud. The situation can be
considered as being similar in some respects to planets orbiting the
sun.

From an electrical point of view, the nucleus is said to be positively
charged and the electrons negatively charged.

From a size point of view, the radius of an atom is about 10^-10^ m
while the radius of a nucleus is about 10^-14^ m, i.e. about ten
thousand times smaller. The situation could be viewed as something like
a cricket ball, representing the nucleus, in the middle of a sporting
arena with the electrons orbiting somewhere around where the spectators
would sit. This perspective tells us that the atom should be composed
mainly of empty space. However, the situation is far more complex than
this simple picture portrays in that we must also take into account the
physical forces which bind the atom together.

Chemical phenomena can be thought of as
interactions between the electrons of individual atoms.
Radioactivity on the other hand can be
thought of as changes which occur within the nuclei of atoms.

## The Nucleus

A simple description of the nucleus tells us that it is composed of
protons and neutrons.
These two particle types are collectively called **nucleons**, i.e.
particles which inhabit the nucleus.

From a mass point of view the mass of a proton is roughly equal to the
mass of a neutron and each of these is about 2,000 times the mass of an
electron. So most of the mass of an atom is concentrated in the small
region at its core.

From an electrical point of view the proton is positively charged and
the neutron has no charge. An atom all on its own (if that were possible
to achieve!) is electrically neutral. The number of protons in the
nucleus of such an atom must therefore equal the number of electrons
orbiting that atom.\

## Classification of Nuclei

The term **Atomic Number** is defined in nuclear physics as the number
of protons in a nucleus and is given the symbol **Z**. From your
chemistry you will remember that this number also defines the position
of an element in the Periodic Table of
Elements.

The term **Mass Number** is defined as the number of nucleons in a
nucleus, that is the number of protons plus the number of neutrons, and
is given the symbol **A**.

Note that the symbols here are a bit odd, in that it would prevent some
confusion if the Atomic Number were given the symbol A, and the Mass
Number were given another symbol, such as M, but its not a simple world!

It is possible for nuclei of a given element to have the same number of
protons but differing numbers of neutrons, that is to have the same
Atomic Number but different Mass Numbers. Such nuclei are referred to as
**Isotopes**. All elements have isotopes and the number ranges from
three for hydrogen to over 30 for elements such as caesium and barium.

Chemistry has a relatively simple way of classifying the different
elements by the use of symbols such as H for hydrogen, He for helium and
so on. The classification scheme used to identify different isotopes is
based on this approach with the use of a superscript before the chemical
symbol to denote the Mass Number along with a subscript before the
chemical symbol to denote the Atomic Number. In other words an isotope
is identified as:

```{=html}
<div class="center">
```
${}_{\mathbf{Z}}^{\mathbf{A}}\mathbf{X}$

```{=html}
</div>
```
where X is the chemical symbol of the element; A is the \"Mass Number,\"
(protons+ neutrons); Z is the \"Atomic Number,\" (number identifying the
element on the periodic chart).

Let us take the case of hydrogen as an example.
It has three isotopes:

-   the most common one consisting of a single proton orbited by one
    electron,
-   a second isotope consisting of a nucleus containing a proton and a
    neutron orbited by one electron,
-   a third whose nucleus consists of one proton and two neutrons, again
    orbited by a single electron.

A simple illustration of these isotopes is shown below. Remember though
that this is a simplified illustration given what we noted earlier about
the size of a nucleus compared with that of an atom. But the
illustration is nevertheless useful for showing how isotopes are
classified.

```{=html}
<div class="center">
```
![](NM2_6Ani.gif "NM2_6Ani.gif")

```{=html}
</div>
```
The first isotope commonly called **hydrogen** has a Mass Number of 1,
an Atomic Number of 1 and hence is identified as:

```{=html}
<div class="center">
```
${}_1^1\mathbf{H}$

```{=html}
</div>
```
The second isotope commonly called **deuterium** has a Mass Number of 2,
an Atomic Number of 1 and is identified as:

```{=html}
<div class="center">
```
${}_1^2\mathbf{H}$

```{=html}
</div>
```
The third isotope commonly called **tritium** is identified as:

```{=html}
<div class="center">
```
${}_1^3\mathbf{H}$

```{=html}
</div>
```
The same classification scheme is used for all isotopes. For example,
you should now be able to figure out that the uranium isotope,
${}_{92}^{236}\mathbf{U}$ , contains 92 protons and 144 neutrons.

A final point on classification is that we can also refer to individual
isotopes by giving the name of the element followed by the Mass Number.
For example, we can refer to deuterium as hydrogen-2 and we can refer to
${}_{92}^{236}\mathbf{U}$ as uranium-236.

Before we leave this classification scheme let us further consider the
difference between chemistry and nuclear physics. You will remember that
the water molecule is made up of two hydrogen atoms bonded with an
oxygen atom. Theoretically if we were to combine atoms of hydrogen and
oxygen in this manner many, many of billions of times we could make a
glass of water. We could also make our glass of water using deuterium
instead of hydrogen. This second glass of water would theoretically be
very similar from a chemical perspective. However, from a physics
perspective our second glass would be heavier than the first since each
deuterium nucleus is about twice the mass of each hydrogen nucleus.
Indeed water made in this fashion is called **heavy water**.

## Atomic Mass Unit

The conventional unit of mass, the kilogram, is
rather large for use in describing characteristics of nuclei. For this
reason, a special unit called the Atomic Mass
Unit (amu) is often used. This unit is
sometimes defined as 1/12th of the mass of the stable most commonly
occurring isotope of carbon, i.e. ^12^C. In terms of grams, 1 amu is
equal to 1.66 x 10^-24^ g, that is, just over one million, million,
million millionth of a gram.

The masses of the proton, m~p~ and neutron, m~n~ on this basis are:

```{=html}
<div class="center">
```
m~p~ = 1.00783 amu

```{=html}
</div>
```
and

```{=html}
<div class="center">
```
m~n~ = 1.00866 amu

```{=html}
</div>
```
while that of the electron is just 0.00055 amu.

## Binding Energy

We are now in a position to consider the subject of nuclear stability.
From what we have covered so far, we have seen that the nucleus is a
tiny region in the centre of an atom and that it is composed of
neutrally and positively charged particles. So, in a large nucleus such
as that of uranium (Z=92) we have a large number of positively charged
protons concentrated into a tiny region in the centre of the atom. An
obvious question which arises is that with all these positive charges in
close proximity, why doesn\'t the nucleus fly apart? How can a nucleus
remain as an entity with such electrostatic repulsion between the
components? Should the orbiting negatively-charged electrons not attract
the protons away from the atoms centre?

Let us take the case of the helium-4 nucleus as
an example. This nucleus contains two protons and two neutrons so that
in terms of amu we can figure out from what we covered earlier that the

```{=html}
<div class="center">
```
mass of 2 protons = 2.01566 amu,

```{=html}
</div>
```
and the

```{=html}
<div class="center">
```
mass of 2 neutrons = 2.01732 amu.

```{=html}
</div>
```
Therefore we would expect the total mass of the nucleus to be 4.03298
amu.

The experimentally determined mass of a helium-4 nucleus is a bit less -
just 4.00260 amu. In other words there is a difference of 0.03038 amu
between what we might expect as the mass of this nucleus and what we
actually measure. You might think of this difference as very small at
just 0.75%. But remember that since the mass of one electron is 0.00055
amu the difference is actually equivalent to the mass of about 55
electrons. Therefore it is significant enough to wonder about.

It is possible to consider that this missing mass is converted to energy
which is used to hold the nucleus together; it is converted to a form of
energy called **Binding Energy**. You could say, as with all
relationships, energy must be expended in order to maintain them!

Like the gram in terms of the mass of nuclei, the common unit of energy,
the joule is rather cumbersome when we consider
the energy needed to bind a nucleus together. The unit used to express
energies on the atomic scale is the **electron volt**, symbol: eV.

One electron volt is defined as the amount
of energy gained by an electron as it falls through a potential
difference of one volt. This definition on its own is not of great help
to us here and it is stated purely for the sake of completeness. So do
not worry about it for the time being. Just appreciate that it is a unit
representing a tiny amount of energy which is useful on the atomic
scale. It is a bit too small in the case of binding energies however and
the mega-electron volt (MeV) is often used.

Albert Einstein introduced us to the
equivalence of mass, m, and energy, E, at the atomic level using the
following equation:

```{=html}
<div class="center">
```
E = m c^2^ ,

```{=html}
</div>
```
where c is the velocity of light.

It is possible to show that 1 amu is equivalent to 931.48 MeV.
Therefore, the mass difference we discussed earlier between the expected
and measured mass of the helium-4 nucleus of 0.03038 amu is equivalent
to about 28 MeV. This represents about 7 MeV for each of the four
nucleons contained in the nucleus.

## Nuclear Stability

In most stable isotopes the binding
energy per nucleon lies between 7 and 9
MeV. There are two competing forces in the nuclei, electrostatic
repulsion between protons and the attractive nuclear force between
nucleons (protons and neutrons). The electrostatic force is a long range
force that becomes more difficult to compensate for as more protons are
added to the nucleus. The nuclear force, which arises as the residual
strong force (the strong force binds the quarks together within a
nucleon), is a short range force that only operates on a very short
distance scale (\~ 1.5 fm) as it arises from a Yukawa potential.
(Electromagnetism is a long range force as the force carrier, the
photon, is massless; the nuclear force is a short range force as the
force carrier, the pion, is massive). Therefore, larger nuclei tend to
be less stable, and require a larger ratio of neutrons to protons (which
contribute to the attractive strong force, but not the long-range
electrostatic repulsion). For the low Z nuclides the ratio of neutrons
to protons is approximately 1, though it gradually increases to about
1.5 for the higher Z nuclides as shown below on the **Nuclear Stability
Curve**.

!The nuclear stability
curve.

In other words to combat the effect of the increase in electrostatic
repulsion when the number of protons increases the number of neutrons
must increase more rapidly to contribute sufficient energy to bind the
nucleus together.

As we noted earlier there are a number of isotopes for each element of
the Periodic Table. It has been found that the most stable isotope for
each element has a specific number of neutrons in its nucleus. Plotting
a graph of the number of protons against the number of neutrons for
these stable isotopes generates what is called the **Nuclear Stability
Curve**:

Note that the number of protons equals the number of neutrons for small
nuclei. But notice also that the number of neutrons increases more
rapidly than the number of protons as the size of the nucleus gets
bigger so as to maintain the stability of the nucleus. In other words
more neutrons need to be there to contribute to the binding energy used
to counteract the electrostatic repulsion between the protons.

## Radioactivity

There are about 2,450 known isotopes of the approximately one hundred
elements in the Periodic Table. You can imagine the size of a table of
isotopes relative to that of
the Periodic Table! The unstable isotopes lie above or below the Nuclear
Stability Curve. These unstable isotopes attempt to reach the stability
curve by splitting into fragments, in a process called **Fission**, or
by emitting particles and/or energy in the form of radiation. This
latter process is called **Radioactivity**.

It is useful to dwell for a few moments on the term radioactivity. For
example what has nuclear stability to do with radio? From a historical
perspective remember that when these radiations were discovered about
100 years ago we did not know exactly what we were dealing with. When
people like Henri Becquerel and Marie
Curie were working initially on these strange
emanations from certain natural materials it was thought that the
radiations were somehow related to another phenomenon which also was not
well understood at the time - that of radio communication. It seems
reasonable on this basis to appreciate that some people considered that
the two phenomena were somehow related and hence that the materials
which emitted radiation were termed *radio-active*.

We know today that the two phenomena are not directly related but we
nevertheless hold onto the term radioactivity for historical purposes.
But it should be quite clear to you having reached this stage of this
chapter that the term radioactive refers to the emission of particles
and/or energy from unstable isotopes. Unstable isotopes for instance
those that have too many protons to remain a stable entity are called
**radioactive isotopes** - and called **radioisotopes** for short. The
term **radionuclide** is also sometimes used.

Finally about 300 of the 2,450-odd isotopes mentioned above are found in
nature. The rest are man-made, that is they are produced artificially.
These 2,150 or so artificial isotopes have been made during the last 100
years or so with most having been made since the second world war.

We will return to the production of radioisotopes in a later
chapter
of this wikibook and will proceed for the time being with a description
of the types of radiation emitted by radioisotopes.

## Multiple Choice Questions

Click
`<b>`{=html}here`</b>`{=html}
to access multiple choice questions on atomic and nuclear structure.

## External Links

-   Novel Periodic
    Table - an
    interactive table providing information about each element.
-   Marie and Pierre Curie and the Discovery of Polonium and
    Radium - an
    historical essay from The Nobel Foundation.
-   Natural
    Radioactivity -
    an overview of radioactivity in nature - includes sections on
    primordial radionuclides, cosmic radiation, human produced
    radionuclides, as well as natural radioactivity in soil, in the
    ocean, in the human body and in building materials - from the
    University of Michigan Student Chapter of the Health Physics
    Society.
-   The Particle
    Adventure -
    an interactive tour of the inner workings of the atom which explains
    the modern tools physicists use to probe nuclear and sub-nuclear
    matter and how physicists measure the results of their experiments
    using detectors - from the Particle Data Group at the Lawrence
    Berkeley National Lab, USA and mirrored at CERN, Geneva.
-   WebElements - an excellent web-based
    Periodic Table of the Elements which includes a vast array of data
    about each element - originally from Mark Winter at the University
    of Sheffield, England.

ca:Física bàsica de la medicina nuclear/Estructura atòmica i
nuclear


# Basic Physics of Nuclear Medicine/Radioactive Decay

!`<span style="color:white;">`{=html}`</span>`{=html}

We saw in the last
chapter
that radioactivity is a process used by unstable nuclei to achieve a
more stable situation. It is said that such nuclei *decay* in an attempt
to achieve stability. So, an alternative title for this chapter is
**Nuclear Decay Processes**.

We also saw in the previous chapter that we can use the Nuclear
Stability Curve as a means of describing what is going on. So a second
alternative title for this chapter is **Methods of Getting onto the
Nuclear Stability Curve**.

We are going to follow a descriptive or phenomenological approach to the
topic here by describing in a fairly simple fashion what is known about
each of the major decay mechanisms. Once again you may have already
covered this material in high school physics. But bear with us because
the treatment here will help us set the scene for subsequent chapters.

## Methods of Radioactive Decay

Rather than considering what happens to individual nuclei it is perhaps
easier to consider a hypothetical nucleus that can undergo many of the
major forms of radioactive decay. This hypothetical nucleus is shown
below:

!A hypothetical nucleus which can undergo many forms of radioactive
decay.{width="320"}

Firstly we can see two protons and two neutrons being emitted together
in a process called **alpha-decay**. Secondly, we can see that a proton
can release a positron in a process called **beta-plus decay**, and that
a neutron can emit an electron in a process called **beta-minus decay**.
We can also see an electron being captured by a proton. Thirdly we can
see some energy (a photon) being emitted which results from a process
called **gamma-decay** as well as an electron being attracted into the
nucleus and being ejected again. Finally there is the rather
catastrophic process where the nucleus cracks in half called
**spontaneous fission**.

We will now describe each of these decay processes in turn.

## Spontaneous Fission

This is a very destructive process which occurs in some heavy nuclei
which split into 2 or 3 fragments plus some neutrons. These fragments
form new nuclei which are usually radioactive. Nuclear
reactors exploit this phenomenon for the
production of radioisotopes. Its also used for nuclear power generation
and in nuclear weaponry. The process is not of great interest to us here
and we will say no more about it for the time being.

## Alpha Decay

In this decay process two protons and two neutrons leave the nucleus
together in an assembly known as an **alpha particle**. Note that an
alpha particle is really a helium-4
nucleus.

So why not call it a helium nucleus? Why give it another name? The
answer to this question lies in the history of the discovery of
radioactivity. At the time when these radiations were discovered we
didn\'t know what they really were. We found out that one type of these
radiations had a double positive charge and it was not until sometime
later that we learned that they were in fact nuclei of helium-4. In the
initial period of their discovery this form of radiation was given the
name alpha rays (and the other two were called beta and gamma rays),
these terms being the first three letters of the Greek alphabet. We
still call this form of radiation by the name **alpha particle** for
historical purposes. Calling it by this name also contributes to the
specific jargon of the field and leads outsiders to think that the
subject is quite specialized!

But notice that the radiation really consists of a helium-4 nucleus
emitted from an unstable larger nucleus. There is nothing strange about
helium since it is quite an abundant element on our planet. So why is
this radiation dangerous to humans? The answer to this question lies
with the energy with which they are emitted and the fact that they are
quite massive and have a double positive charge. So when they interact
with living matter they can cause substantial destruction to molecules
which they encounter in their attempt to slow down and to attract two
electrons to become a neutral helium atom.

An example of this form of decay occurs in the
uranium-238 nucleus. The equation which
represents what occurs is:

```{=html}
<div style="text-align:center;">
```
${}_{\mathbf{92}}^{\mathbf{238}}\mathbf{U}$ →
${}_{\mathbf{90}}^{\mathbf{234}}\mathbf{Th}$

`+ `${}_{\mathbf{2}}^{\mathbf{4}}\mathbf{He}$

```{=html}
</div>
```
Here the uranium-238 nucleus emits a helium-4 nucleus (the alpha
particle) and the parent nucleus becomes thorium-234. Note that the Mass
Number of the parent nucleus has been reduced by 4 and the Atomic Number
is reduced by 2 which is a characteristic of alpha decay for any nucleus
in which it occurs.

## Beta Decay

There are three common forms of beta decay:

**(a) Electron Emission**

:   Certain nuclei which have an excess of neutrons may attempt to reach
    stability by converting a neutron into a proton with the emission of
    an electron. The electron is called a **beta-minus particle** -- the
    minus indicating that the particle is negatively charged.

```{=html}
<!-- -->
```

:   We can represent what occurs as follows:

```{=html}
<div class="center">
```
n^0^ → p^+^ + e^-^

```{=html}
</div>
```

:   where a neutron converts into a proton and an electron. Notice that
    the total electrical charge is the same on both sides of this
    equation. We say that the electric charge is
    conserved.

```{=html}
<!-- -->
```

:   We can consider that the electron cannot exist inside the nucleus
    and therefore is ejected.

```{=html}
<!-- -->
```

:   Once again there is nothing strange or mysterious about an electron.
    What is important though from a radiation safety point of view is
    the energy with which it is emitted and the chemical damage it can
    cause when it interacts with living matter.

```{=html}
<!-- -->
```

:   An example of this type of decay occurs in the
    iodine-131 nucleus which decays into xenon-131
    with the emission of an electron, that is

```{=html}
<div class="center">
```
${}_{\mathbf{53}}^{\mathbf{131}}\mathbf{I}$

`→ `${}_{\mathbf{54}}^{\mathbf{131}}\mathbf{Xe}$` + `${}_{\mathbf{-1}}^{\mathbf{0}}\mathbf{e}$

```{=html}
</div>
```

:   The electron is what is called a beta-minus particle. Note that the
    Mass Number in the above equation remains the same and that the
    Atomic Number increases by 1 which is characteristic of this type of
    decay.

```{=html}
<!-- -->
```

:   You may be wondering how an electron can be produced inside a
    nucleus given that the simple atomic description we gave in the
    previous chapter indicated that the nucleus consists of protons and
    neutrons only. This is one of the limitations of the simple
    treatment presented so far and can be explained by considering that
    the two particles which we call protons and neutrons are themselves
    formed of smaller particles called **quarks**. We are not going to
    consider these in any way here other than to note that some
    combinations of different types of quark
    produce protons and another combination produces neutrons. The
    message here is to appreciate that a simple picture is the best way
    to start in an introductory text such as this and that the real
    situation is a lot more complex than what has been described. The
    same can be said about the treatment of beta-decay given above as we
    will see in subsequent chapters.

**(b) Positron Emission**

:   When the number of protons in a nucleus is too large for the nucleus
    to be stable it may attempt to reach stability by converting a
    proton into a neutron with the emission of a positively-charged
    electron.

```{=html}
<!-- -->
```

:   That is not a typographical error! An electron with a positive
    charge also called a **positron** is emitted. The positron is the
    **beta-plus particle**.

```{=html}
<!-- -->
```

:   The history here is quite interesting. A brilliant Italian
    physicist, Enrico Fermi developed a
    theory of beta decay and his theory predicted that
    positively-charged as well as negatively-charged electrons could be
    emitted by unstable nuclei. These particles could be called pieces
    of anti-matter and they were
    subsequently discovered by experiment. They do not exist for very
    long as they quickly combine with a normal electron and the
    subsequent reaction called **annihilation** gives rise to the
    emission of two gamma rays.

```{=html}
<!-- -->
```

:   Science fiction writers had a great time following the discovery of
    anti-matter and speculated along with many scientists that parts of
    our universe may contain negatively-charged protons forming nuclei
    which are orbited by positively-charged electrons. But this is
    taking us too far away from the topic at hand!

```{=html}
<!-- -->
```

:   The reaction in our unstable nucleus which contains one too many
    protons can be represented as follows:

```{=html}
<div class="center">
```
p^+^ → n^0^ + e^+^

```{=html}
</div>
```

:   Notice, once again, that electric charge is conserved on each side
    of this equation.

```{=html}
<!-- -->
```

:   An example of this type of decay occurs in
    sodium-22 which decays into neon-22 with the
    emission of a positron:

```{=html}
<div class="center">
```
${}_{\mathbf{11}}^{\mathbf{22}}\mathbf{Na}$ →
${}_{\mathbf{10}}^{\mathbf{22}}\mathbf{Ne}$ +
${}_{\mathbf{+1}}^{\mathbf{0}}\mathbf{e}$

```{=html}
</div>
```

:   Note that the Mass Number remains the same and that the Atomic
    Number decreases by 1.

**(c) Electron Capture**

:   In this third form of beta decay an inner orbiting electron is
    attracted into an unstable nucleus where it combines with a proton
    to form a neutron. The reaction can be represented as:

```{=html}
<div class="center">
```
e^-^ + p^+^ → n^0^

```{=html}
</div>
```

:   This process is also known as **K-capture** since the electron is
    often attracted from the K-shell of the atom.

```{=html}
<!-- -->
```

:   How do we know that a process like this occurs given that no
    radiation is emitted? In other words the event occurs within the
    atom itself and no information about it leaves the atom. Or does it?
    The signature of this type of decay can be obtained from effects in
    the electron cloud surrounding the nucleus when the vacant site left
    in the K-shell is filled by an electron from an outer shell. The
    filling of the vacancy is associated with the emission of an
    X-ray from the electron cloud and it is
    this X-ray which provides a signature for this type of beta decay.

```{=html}
<!-- -->
```

:   This form of decay can also be recognised by the emission of
    gamma-rays from the new nucleus.

```{=html}
<!-- -->
```

:   An example of this type of radioactive decay occurs in
    iron-55 which decays into manganese-55
    following the capture of an electron. The reaction can be
    represented as follows:

```{=html}
<div class="center">
```
${}_{\mathbf{26}}^{\mathbf{55}}\mathbf{Fe}$ +
${}_{\mathbf{-1}}^{\mathbf{0}}\mathbf{e}$ →
${}_{\mathbf{25}}^{\mathbf{55}}\mathbf{Mn}$

```{=html}
</div>
```

:   Note that the Mass Number once again is unchanged in this form of
    decay and that the Atomic Number is decreased by 1.

## Gamma Decay

Gamma decay involves the emission of energy from an unstable nucleus in
the form of electromagnetic radiation.

You should remember from your high school physics that electromagnetic
radiation is the biggest
physical phenomenon we have so far discovered. The radiation can be
characterised in terms of its frequency, its wavelength and its energy.
Thinking about it in terms of the energy of the radiation we have very
low energy electromagnetic radiation called **radio waves**, **infra-red
radiation** at a slightly higher energy, **visible light** at a higher
energy still, then **ultra-violet radiation** and the higher energy
forms of this radiation are called **X-rays** and **gamma-rays**. You
should also remember that these radiations form what is called the
Electromagnetic Spectrum.

```{=html}
<div class="center">
```
![](NM3_11.gif "NM3_11.gif")

```{=html}
</div>
```
Before proceeding it is useful to pause for a moment to consider the
difference between X-rays and gamma-rays. These two forms of radiation
are high energy electromagnetic rays and are therefore virtually the
same. The difference between them is not **what** they consist of but
**where** they come from. In general we can say that if the radiation
emerges from a nucleus it is called a gamma-ray and if it emerges from
outside the nucleus from the electron cloud for example, it is called an
X-ray.

One final point is of relevance before we consider the different forms
of gamma-decay and that is what such a high energy ray really is. It has
been found in experiments that gamma-rays (and X-rays for that matter!)
sometimes manifest themselves as waves and other times as particles.
This wave-particle duality can be
explained using the equivalence of mass and energy at the atomic level.
When we describe a gamma ray as a wave it has been found useful to use
terms such as frequency and wavelength just like any other wave. In
addition when we describe a gamma ray as a particle we use terms such as
mass and electric charge. Furthermore the term electromagnetic
photon is used for these particles. The
interesting feature about these photons however is that they have
neither mass nor charge!

There are two common forms of gamma decay:

**(a) Isomeric Transition**

:   A nucleus in an excited state may reach its ground or unexcited
    state by the emission of a gamma-ray.

```{=html}
<!-- -->
```

:   An example of this type of decay is that of
    technetium-99m -- which by the way is the
    most common radioisotope used for diagnostic purposes today in
    medicine. The reaction can be expressed as:

```{=html}
<div class="center">
```
${}_{\mathbf{43}}^{\mathbf{99m}}\mathbf{Tc}$ →
${}_{\mathbf{43}}^{\mathbf{99}}\mathbf{Tc}$ +
`<b>`{=html}`<big>`{=html}$\gamma$`</big>`{=html}`</b>`{=html}

```{=html}
</div>
```

:   Here a nucleus of technetium-99 is in an excited state, that is, it
    has excess energy. The excited state in this case is called a
    **metastable state** and the nucleus is therefore called
    technetium-99m (m for metastable). The excited nucleus looses its
    excess energy by emitting a gamma-ray to become technetium-99.

**(b) Internal Conversion**

:   Here the excess energy of an excited nucleus is given to an atomic
    electron, e.g. a K-shell electron.

## Decay Schemes

Decay schemes are widely used to give a
visual representation of radioactive decay. A scheme for a relatively
straight-forward decay is shown below:

![](NM3_12.gif){width="150"}

This scheme is for hydrogen-3 which decays to helium-3 with a half-life
of 12.3 years through the emission of a beta-minus particle with an
energy of 0.0057 MeV.

A scheme for a more complicated decay is that of caesium-137.

![](NM3_13.gif){width="150"}

This isotope can decay through through two beta-minus processes. In one
which occurs in 5% of disintegrations a beta-minus particle is emitted
with an energy of 1.17 MeV to produce barium-137. In the second which
occurs more frequently (in the remaining 95% of disintegrations) a
beta-minus particle of energy 0.51 MeV is emitted to produce barium-137m
-- in other words a barium-137 nucleus in a metastable state. The
barium-137m then decays via isomeric transition with the emission of a
gamma-ray of energy 0.662 MeV.

![](NM3_14.gif)

The general method used for decay schemes is illustrated in the diagram
on the right.

The energy is plotted on the vertical axis and atomic number on the
horizontal axis -- although these axes are rarely displayed in actual
schemes. The isotope from which the scheme originates is displayed at
the top -- X in the case above. This isotope is referred to as the
**parent**. The parent loses energy when it decays and hence the
products of the decay referred to as **daughters** are plotted at a
lower energy level.

The diagram illustrates the situation for common forms of radioactive
decay. Alpha-decay is illustrated on the left where the mass number is
reduced by 4 and the atomic number is reduced by 2 to produce daughter
**A**. To its right the scheme for beta-plus decay is shown to produce
daughter **B**. The situation for beta-minus decay followed by
gamma-decay is shown on the right side of the diagram where daughters
**C** and **D** respectively are produced.

## Multiple Choice Questions

Click
`<b>`{=html}here`</b>`{=html}
to access multiple choice questions on radioactive decay.

## External links

-   Basics about
    Radiation --
    overview of the different types of ionising radiation from the
    Radiation Effects Research Foundation -- a cooperative Japan-United
    States Research Organization which conducts research for peaceful
    purposes.
-   Radiation and Life
    -- from the World Nuclear Association website.
-   Radiation and
    Radioactivity
    -- a self-paced lesson developed by the University of Michigan\'s
    Student Chapter of the Health Physics Society, with sections on
    radiation, radioactivity, the atom, alpha radiation, beta radiation
    and gamma radiation.