Question

The valencies (or charges) of some of the ions are given below : 

Ion	Valency (Charge)	Ion	Valency (Charge)
Sodium ion	1+	Bromide ion	1–
Ammonium ion	1+	Hydroxide ion	1–
Calcium ion	2+	Sulphate ion	2–
Lead ion	2+	Phosphate ion	3–

Using this information, write down the formulae of the following compounds :
(i) Sodium phosphate
(ii) Ammonium sulphate
(iii) Calcium hydroxide
(iv) Lead bromide 

Answer 1

Formula of the listed compounds are as follows:
Sodium phosphate –      Na₃PO₄

Ammonium sulphate –   (NH₄)₂SO₄

Calcium hydroxide –     Ca(OH)₂

Lead bromide –            PbBr₂