CHEMISTRY Do as Directed.

When an atom loses or gains electrons, it becomes a charged particle called ion. When an atom loses one or more electrons, it forms a positive ion called cation, e.g. Na+ (sodium ion). When an atom gains one or more electrons, it forms a negative ion called anion e.g. CT (chloride ion).

Valency is the number of electrons an atom can donate or gain to form a chemical bond with another atom. It is the combining capacity of an atom of an element. For example, in the formation of sodium chloride’s the sodium atom donates one electron that is accepted by the chlorine atom. Therefore, the valency of sodium is 1 and that of chlorine is also 1.

A chemical bond is a force of attraction which bonds the atoms of a compound together.

Magnesium chloride

Calcium carbonate

Potassium nitrate

Potassium sulphate

Aluminium sulphate

Ag

Cu

Fe

K

Na

Polyatomic or compound ion

Anion

Cation

Chemical bond

Electron

Atom

Potassium

Diamond