ion

Atom, or group of atoms, that is either positively charged (cation) or negatively charged (anion), as a result of the loss or gain of electrons during chemical reactions or exposure to certain forms of radiation. In solution or in the molten state, ionic compounds such as salts, acids, alkalis, and metal oxides give rise to mobile ions and therefore conduct electricity. These compounds are known as electrolytes.

Ions are produced during electrolysis, for example the salt zinc chloride (ZnCl₂) dissociates into the positively-charged Zn²⁺ and negatively-charged Cl^- when electrolysed.