(a) What is the difference between a cation and an anion ? Explain with examples.(b) The valencies (or charges) of some of the ions are given below : Ion Valency (Charge) Ion Valency (Charge)Sodium ion 1+ Nitrate ion 1–Copper ion 2+ Sulphide ion 2–Using this information, write down the formulae of :(i) Sodium sulphide(ii) Copper nitrate

Cation	Anion
When a neutral atom loses one or more electrons, it develops an overall positive charge and becomes a cation.	When a neutral atom gains one or more electrons, it develops an overall negative charge and becomes an anion.
A cation has fewer electrons than the neutral (normal) atom of that element.	An anion has more electrons than the neutral (normal) atom of that element.
Example: Sodium atom readily loses an electron to form a positively charged sodium ion. Na → Na+ + e−	Example: Chlorine atom accepts an electron to become a negatively charged chloride ion. Cl + e− → Cl−

(b) The formula of the given compounds are given below:

(i) Sodium sulphide: Na₂S