Write the chemical formulae and names of the compounds formed by the following ions:

(i) Cr³⁺ and SO₄^2–

(ii) Pb2+ and NO₃^–

(iii) Mg²⁺ and CO₃^2–

(i) Cr³⁺ and SO₄^2-

By applying criss-cross method:

Chemical formula: Cr₂(SO₄)₃

Name of the compound: Chromium sulphate

(ii) Pb²⁺ and NO₃^–

By applying criss-cross method:

Chemical formula: Pb(NO₃)

Name of the compound: Lead nitrate

(iii) Mg²⁺ and CO₃^2–

By applying criss-cross method:

Chemical formula: MgCO₃

Name of the compound: Magnesium carbonate