Write the symbols and valencies of the following radicals:

(a) Magnesium ion

(b) Ammonium

(c) Carbonate

(d) Nitrate

(e) Oxide

(f) Bisulphate

(g) Aluminium ion

Name the following radicals:

(a) SO₄^2-

(b) HCO₃^-

(c) OH^-

(d) Cr₂O₇^2-

Name one ion for each of the valencies -1, -2 and -3.

The valency of calcium is 2. Write the valencies of other radicals in the following compounds:

(a) CaO

(b) Ca(OH)₂

(c) CaCO₃

(d) CaCl₂