### element:

Chlorine
* Follow the directions on the packet of sodium or calcium hypochlorite.
* Helps clean out the nitrogen and end products of metabolism.
* More chlorines mean a longer life.
* Most chlorine has mass
  - is used at the site of manufacture
* Some chlorine kills fish
  - reacts with oxygen
* acts as a catalyst to instantly precipitate iron which then can be captured in a filter
  - to separate the lignin from the pulp which can then be removed
* affects flavor and dampens the activity of yeast.
* alone yellow gas.
* also has a multitude of industrial uses
  - limited effectiveness against some micro-organisms and none against chemicals
  - helps create the hard plastic used to make protective helmets and face shields
  - increases efficiency
  - kills the priceless friendly bacteria in the colon
  - oxidizes iron and manganese so they can be filtered out
* also plays a critical role in the production of thousands of commercial products
  - role in the classroom
  - reacts with chemicals in the water to form strong cancer-causing compounds
* attacks the alloys in gold.
* based washes are very effective against mildew and other decay organisms.
* becomes argon when it interacts with electron neutrinos.
* begins evaporating when mixed.
* belongs to the group of elements called halogens
  - halogen family of elements, found in group VIIa of the periodic table
* bonding with oxygen destroys the ozone molecules.
* building block for nearly all chemical processes.
* burns the gills.
* calcium antagonist.
* can affect infant airways
  - also react with alkenes via the electrophilic addition mechanism
  - be fatal after only a few deep breaths
  - break down and pit gold alloys if exposed often enough
* can cause bleached hair to turn green
  - blistering of the gills and suffocation
  - cause, and worsens, skin irritations and rashes
  - clear up any skin problem
  - combine with ammonia and nitrogen compounds to create chloramines
  - contribute some adverse effects however
  - damage ozone
  - harm fish and aquatic plants
  - have an irritating effect
  - kill beneficial bacteria in the body
  - make skin dry and flaky
  - metabolize into an estrogen-like substance inside the human body
  - put a lid on the development of yeast
  - replace hydrogen on the outside of the ring
  - wreak havoc with hair condition
* causes environmental harm at low levels.
* central component of the world synthetic market.
* chemical that kills microorganisms
  - used to disinfect water
* combines with all elements except the noble gases
  - almost all elements to produce chlorides
* comes in numerous chemical forms and methods of application.
* common oxidant which is added to most public water supplies for disinfection purposes.
* commonly used oxidant.
* compounds together with chloramines form combined chlorine.
* consists of the following isotopes.
* constitutes about two-thirds of the total anions of blood plasma.
* corrodes the alloy that is part of yellow or white gold jewelry.
* damages the gills - the affects of many small doses of chlorine can add up to major damage.
* deactivates a variety of microorganisms at rates dependent on the species.
* degrades water quality and negatively impacts aquatic life.
* destroys Ozone faster than it can be replenished
* destroys the microbes responsible for disease
  - natural bacterial balance of the skin
  - vitamin E in the body, which is absolutely essential for the health of the heart
* disinfectant that destroys disease-causing organisms
  - used to remove harmful bacteria from the drinking water
* displaces the less electronegative halogens from compounds.
* does much more than kill microorganisms in the nation's water supply
  - purify swimming pool water
  - sanitize the wash water and maintains a low microbiological count in the water
* effectively increases the removal of organic residues.
* exhibits a complex reaction to temperature.
* forms several oxides.
  - at room temperature
* gives vinyl two advantages.
* great bacteria and virus killer.
* green, corrosive gas, which causes a severe choking sensation.
* green-yellow gas.
* greenish highly poisonous liquefiable gas.
* greenish yellow gas at normal temperature and pressure
  - which combines directly with nearly all elements
* greenish-yellow gas that can be combined directly with nearly every element
  - is slightly soluble in water
  - with a strong irritating odor
  - gas, two and one half times as heavy as air
* greenish-yellow, poisonous gas with a disagreeable, suffocating odor.
  - that damages enzymes
* has a bad reputation
  - characteristic penetrating and irritating odor
  - distinctive green-yellow color
  - pungent, irritating odor similar to bleach that is detectable at low concentrations
  - residual effect, which means it works for a while after being added to the water
  - sharp, irritating and penetrating odor
  - shelf life of six months, so be sure to use fresh bleach
  - strong chemical attraction for ozone
  - tendency to gain one electron
  - variety of uses
  - wide range of isotopes
  - diverse applications across many product sectors
  - many uses , including keeping drinking water safe
* has the capacity to take in two electrons, whereas chlorine dioxide can absorb five
  - same effect
* has two naturally occurring isotopes
  - stable isotopes
* hazardous gas that is strongly corrosive.
* helps make possible many of the miracles of modern medicine
  - purify water and prevents bacterial infections
  - remove manganese and hydrogen sulfide in the same way
* highly corrosive chemical, especially in concentrated form
  - effective spot algicide
* highly reactive element
* irritates eyes and skin, bleaches swimwear and shortens the life of vinyl pool liners
  - eyes, nose membranes, and lungs and it leaves skin and hair dry and flaky
  - the skin, the eyes, and the respiratory system
* is absorbed chiefly from the small intestine
  - actually a more powerful disinfectant than chloramine
* is added again after filtration for post-disinfection
  - as a disinfectant according to state and federal regulations
* is added for destruction of harmful bacteria in the water
  - disinfection to prevent disease
  - virus inactivation and to kill any bacteria
  - into the waste water flow at the influent pipe
  - to city water supplies to control bacteria and living organisms
* is added to disinfect the finished water
  - wastewater and to kill pathogenic organisms
  - water from any microbial containments
* is added to drinking water as a solution
  - either a gas or after having been already dissolved in water
* is added to keep bacteria from developing in the water
  - the water supply safe
* is added to kill any bacteria and fluoride is added for the prevention of tooth decay
  - bacteria in water pipes
  - harmful bacteria, protozoans and viruses
  - most countries drinking water to protect against bacteria
  - swimming pools to keep the water safe for swimming
* is added to the flow as it enters the chlorine contact chamber
  - incoming water to kill micro-organisms
  - wastewater to destroy bacteria
* is added to the water as a disinfectant to kill harmful bacteria and viruses
  - dump or rinse at the packhouse to prevent the spread of spores
* is added to the water for a final disinfection
  - disinfection to protect against waterborne diseases
* is added to the water to kill bacteria, and fluoride is added to help prevent tooth decay
  - kill most disease-causing organisms
  - wastewater as a disinfectant before it is discharged
  - water leaving the greenhouse as a final disinfection stage
* is also a highly corrosive substance, capable of damaging skin, eyes, and other membranes
  - small contributor to ozone destruction
* is also an essential component in the production of many life-saving pharmaceuticals
  - important participant in complex natural atmospheric chemical reactions
  - oxidizer used in purifying drinking water
  - dangerous to transport and store
  - familiar as a bleaching agent
  - important in the manufacture of paints, aerosol propellants and plastics
  - widely used in drinking water purification and waste-water disinfection
* is an active element, reacting with water , organic compounds, and many metals
  - acutely toxic chemical
* is an effective disinfectant and bleach
  - treatment, however, because it destroys the food supply of Legionella
  - emotive subject
  - essential elemental building block
* is an example of a metal
  - p-block element
  - important constituent of many poison gases
  - inhibitor of the endocrine system and a major carcinogen
  - applied in either a gas, liquid or dry form
* is available as solid tablets for swimming pools
  - in either gas, liquid, or solid forms
  - bubbled through a solution of calcium iodide to produce calcium chloride and iodine
  - central to water purification and eliminating disease
  - chemical elements
  - chemically very active
  - contained in appreciable amounts in most fertilizer mixtures
  - derived from salt, and used to make vinyls
  - dissipated rapidly by sunlight
  - drawn off only one cylinder at a time
  - effective against bacteria and many viruses
* is effective in killing polyoma as are many commercially available disinfectants
* is emitted as hydrochloric acid into the atmosphere
  - from acid regeneration plants
* is especially harmful to organisms living in water and in soil
  - harsh on children's sensitive skin and hair
* is essential for certain digestive enzymes and for carbon dioxide transport
  - in producing many life-saving medicines
  - to human life
  - evolved because it is in high concentration
* is extremely damaging to the hair and scalp
  - toxic to fish and other aquatic life
* is fed into the water in gaseous form
  - to kill pathogenic bacteria, and to reduce unpleasant odors
* is found as a heavy yellowish green gas
  - largely in seawater where it exists as sodium chloride
  - generally toxic to fish and other aquatic life
  - greenish colored gas
  - hard on everyting it comes in contact with, spa covers, skin filters
  - harmful to land hermit crabs
  - heavier than air and the cloud formed tends to spread along the ground
* is highly reactive
  - toxic to fish and life in general
  - housed indoors, so gas leaks are less severe
  - in a group of elements having seven electrons in their outer shells
  - inactivated in the presence of organic material
  - injected to keep bacteria from growing in the distribution system mains
  - instantaneously and almost inexhaustibly oxidized
  - introduced to the remaining water for disinfection to kill any remaining bacteria
  - irreplaceable in our economy
  - irritants
  - known to form numerous compounds after it is added to municipal water supplies
* is less reliable than iodine for chemical disinfection
  - stable then chloramine and airs out in just a few days
  - lethal in an enclosed space
  - liberated at the anode
  - located in swimming pools
* is manufactured commercially by running an electric current through salt water
  - from potassium chloride, as well as sodium chloride, or table salt
  - in two ways
* is measured in the field using a portable instrument
  - portable analytical instrumentation
* is more active than iodine
  - effective in colder water
* is more electronegative and attracts the electrons more strongly
  - than hydrogen
  - susceptible to reduction to chloride in more acidic conditions
  - naturally present as organic compounds in the sea, in rivers and in plants
* is necessary for proper functioning of a human body
  - in order to kill certain bacteria that are harmful to people
* is needed to maintain disinfection throughout the distribution system
  - the water distribution system
  - neither explosive nor flammable
* is one chemical that is used to treat drinking water
  - used to purify water
  - of a number of substances that undergo photochemical reactions
* is one of the most common elements in nature
  - commonly perceived tastes associated with municipal water
  - important basic chemicals in the chemical industry
  - toxic elements found in nature
  - ten most important industrial chemicals
  - universe's basic elements
* is present in most city water supplies
* is produced commercially by the electrolysis of sodium chloride
  - the electrolysis of salt water
  - quite toxic when inhaled
  - rare in the atmosphere
  - reacted with seawater to change the iodide to iodine
  - reactive , very corrosive , and very poisonous
  - reduced at the cathode
  - released very quickly
  - removed and minerals are added for taste
  - represented by a green object
  - required in photosythesis
  - safe at the levels used for water treatment
  - shipped as a liquid in steel bottles or tank cars
  - so toxic that it was used during World War II as a poison gas
  - stable in steel containers at room temperature when dry
  - still the most effective way of disinfecting domestic wastewater
* is the chemical added to water for disinfection
  - fish killing agent
  - greatest cripple and killer of the modern times
* is the main chemical used to clean the water, mostly because it is cheapest
  - compound which reduces the ozone layer in the upper atmosphere
  - most common chemical disinfectant, but ozone is also an important option
* is the most common disinfectant used in the United States and Canada
  - to treat drinking water and swimming pools
  - pool disinfectant and is effective against most germs
* is the most effective anion in lowering urine pH and, therefore, making blood more acidic
  - killer of bacteria in water supplies
  - important chemical added to water in terms of public health
* is the most widely applied disinfecting agent for swimming pool water
  - used drinking water disinfectant in North America
  - name of the element
* is toxic and for that reason is extremely anti-bacterial
  - treated somewhat differently
* is used as a bleach and disinfectant
  - disinfectant against waterborne microbiological infections
* is used by the city as a disinfectant
  - paper industry for two purposes
* is used extensively in polymers and in organic chemistry
  - the treatment of our water system to make it safe to drink
* is used for disinfection and odor control
  - producing safe drinking water all around the world
* is used in industry and in household cleaning products
  - pools and drinking water because it great disinfectant
  - small quantities in swimming pools and hot tubs
* is used in water and swimming pools
  - purification because it is effective and it is persistent
  - purification, and as a disinfectant and antiseptic
  - most often to disinfect private wells
* is used to assure the bacterial safety of the drinking water
  - clean out germs in water
  - control bacteria in the sanitary plant effluent
* is used to disinfect drinking water supplies, pool water and sewage treatment effluent
  - municipal water supplies and water in swimming pools
* is used to disinfect the plant effluent before it is discharged to the Town Branch Creek
* is used to kill disease-causing organisms and for odor control
  - microbes in many treatment facilities
* is used to make many products, including paper, plastic, paint and pesticides
  - water clearer and purer
  - manufacture each of the following products
  - remove any hazardous bacteria
  - worldwide to ensure that water is drinkable
* is very active and is used in acids and bleaches which kill germs
  - bad for hermit crabs
* is very effective against algae , bacteria and viruses
  - bacteria but less effective against viruses and protozoa
  - harmful to fish
  - irritating and greenish-yellow gas
  - soluble in water so is simply dissolved in the supply
  - virtually ineffective on crypto at levels typically used for disinfection
* is, essentially, bleach.
* keeps tap water clean and is the key to the manufacture of pharmaceuticals.
* kills any remaining bacteria left in the water
  - living creatures, and can be harmful to birds
  - microbes in tap water and swimming pools
  - the good flora in the intestinal tract
* major environmentally destructive agent
  - source of dioxin, one of the most toxic chemicals the world has ever known
* makes hair brittle and dry, and can make sensitive skin flaky and itchy
  - sure that nothing can live in the water
  - up two percent by weight of all sea water on Earth
* member of the halogen family.
* method of disinfection commonly used for drinking water.
* needs time to kill iron bacteria.
* notoriously causes hair to become brittle.
* noxious and corrosive yellow-green chemical
  - dangerous gas
* occurs both inside and outside the cell
  - naturally in the oceans
* often irritates the eyes and lungs.
* plays havoc with our skin and hair, chemically bonding with the protein in our bodies.
* poison present in nearly all dishwashing detergents.
* poisonous greenish-yellow gas with a strong, bad smell.
* poisonous, greenish-yellow gas described as having a choking odor.
* potent irritant to the eyes, lungs and skin.
* powerful irritant that can inflict damage to the eyes, nose, throat and lungs.
* prevents water-borne epidemics such as cholera, typhoid, and hepatitis.
* process gas.
* produces by-products that contribute to cancer and birth defects.
* protects our system from bacterial growth.
* ranks third in electronegativity.
* reactive yellow-green gas.
* reacts readily with hydrogen to form hydrogen chloride
  - specifically with the copper and nickel portions of gold jewelry alloys
  - to create new carcinogens
* reacts with and destroys ozone molecules, making holes in the ozone layer
  - bromides and iodides to make bromine and iodine
  - certain metals and organic matter in the water
  - dissolved iron to form particles of iron that settle out of the water
  - hydrogen sulfide and water forming hydrochloric acid
* reacts with many elements of both metals and nonmetals to give chlorides
  - organic compounds to form chlorinated derivatives
* reacts with naturally occurring organic compounds in the water to form haloforms
  - matter and forms chlorinated and brominated DBPs
* reacts with organic material to form carcinogenic compounds
  - nitrogenous matter in the water
  - white phosphorus forming phosphorus trichloride and phosphorus pentachloride
* reduces odorous tastes in the water.
* remains the most popular form of pool sanitation.
* respiratory irritant.
* salt in solution.
* saves lives.
* serves as a catalyst for a process that destroys ozone, turning it into breathable oxygen.
* special gas.
* speeds the degradation for all of the dyes.
* strong bleach and is dangerous
  - oxidant, oxidizing metals to form their chlorides
  - oxidizing agent and as a result is effective in killing bacteria
  - powerful oxidant which can promote corrosion
* substance that is relatively easy to remove.
* surface sterilant.
* tends to be taken for granted.
* toxic gas that attacks living cells
  - the respiratory system, eyes, and skin
* toxic, deadly chemical
  - pale, yellow-green gas with an irritating odor and low solubility in water
* typical nonmetal.
* venom that slowly poisons the animals, causes blindness and, eventually, death.
* very active element
  - dangerous material
* very reactive chemical and can damage the steel's oxide coating
  - safe and efficient way of killing bacteria in water supplies
  - strong chemical that destroys sperm pretty quickly
* well proven disinfectant for the prevention of water borne disease outbreaks.
* works because it powerful and toxic oxidizing agent
  - better in warmer water
* yellow-green gas at room temperature.
* yellowish green gas with a strong bleach smell and is quite toxic.
+ Chlorine, Properties, Chemical properties
  * Chlorine is highly reactive. It is more reactive than bromine but less reactive than fluorine. It reacts with most things to make chlorides. It can even burn things instead of oxygen. It dissolves in water to make a mixture of hypochlorous acid and hydrochloric acid. Chlorine reacts with bromides and iodides to make bromine and iodine
  - Physical properties: Chemical elements :: Halogens
  * Chlorine is very irritating and greenish-yellow gas. It has a strong smell like bleach. It is toxic. It can be made into a liquid when cooled. It is heavier than air
+ Iodine, Preparation: Halogens :: Chemical elements :: Nonmetals
  * Kelp was burned and the iodine extracted from the ashes in the 18th and 19th century, but now it is not good enough for common use. Most iodine now is extracted from seawater. Chlorine is reacted with seawater to change the iodide to iodine. Air is blown over the water to evaporate the iodine. Then the iodine is reduced with sulfur dioxide to hydriodic acid. Then the hydriodic acid is oxidized with chlorine again to make iodine. This process is repeated until the iodine is pure.