### ion:

Small ion
* have a greater velocity than large ones and reach the detector first.
* move fairly easily.

### ion:

Sodium ion
* are a product of the reaction
  - found in the ocean
  - kept on the outside of the cells membrane
* are positive, and chloride ions are negative, that's why they stick together as salt
  - so the area immediately outside the cell membrane is positive
  - the dominant cation in the soil solution iv
  - used to build up electrical gradients in the firing of neurons in the brain
* balanced by other ions are necessary to normal cell function in all tissues of the body.
* can displace essential plant nutrients in the soil.
* enter the cell and begin the depolarization
* follow passively.
* increase the activity when magnesium ions are present.
* travel down the axon.
+ Sodium, Occurrence and production: Alkali metals :: Chemical elements
  * It exists as an ion in chemical compounds. Sodium ions are found in the ocean. It is also found as sodium chloride in the earth's crust, where it is mined.

Zinc ion
* are effective antimicrobial agents even at low concentrations.
* inhibit replication of rhinoviruses.
* is also strongly anti inflammatory.
* produce a white precipitate, and cadmium ions a yellow one.
* seem to promote the emigration, implantation and outgrowth of circulating tumour cells.

Ionic compound
* All ionic compounds are electrolytes
  - liquids at room temperature
* Many ionic compounds have water molecules incorporated into their crystalline structures.
* Most ionic compounds have properties.
* Some ionic compounds conduct electricity
  - dissolve in water
  - form crystal
* are always neutral
  - combinations of positive and negative ions
  - crystalline in nature
* are hard, brittle solids with high melting points
  - yet brittle
  - inanimate objects
  - ones that contain metal and nonmetal or ions
  - therefore solids at room temperature
  - usually crystalline solids with a high melting point
* conduct electricity when they are molten or in aqueous solution.
* dissociate to more than one mole of particles.
* have every ion in a fixed position
  - formulas which are empirical formulas
  - many more atoms and their size varies from one molecule to the next
  - one and only one formula
  - strong electric charges holding the ions together and exist as solids
* melt at higher temperatures than covalent compounds
  - lower temperatures than covalent compounds
* transfer electrons from one atom to another.

### ionizing radiation:

Alpha ray
* are actually heavy, fast-moving particles with a positive charge
  - helium nuclei, emitted in strong interactions
  - less energetic than beta or gamma rays, which are associated with nuclear weapons
* have a net positive charge
  - small penetrating power
* is ionizing radiation
* result from the decay of many radioactive elements naturally.

Beta ray
* are also particles, but very much lighter and faster moving than alpha-paricles
  - electrons that come from the nucleus a
  - especially dangerous when emitted inside the body
* can pass through paper and travel a few feet.
* consists of negatively and positively charged electrons.
* have a net negative charge.
  - the name given to the emerging electron
* sit in seeds at the tip of a long catheter.