Give reasons for the following:
(i) Zn⁺² salts are white but Cu²⁺ salts are blue in colour.
(ii) Fluorine gives only one oxide but chlorine gives a series of oxides.

(i) Cu²⁺ salts are coloured because they absorb visible light for excitation of electrons to partly filled d-orbitals. Zn²⁺ salts are colourless because of the absence of partly filled d-orbitals to which the electrons can be oxidized.

(ii) Fluorine does not have d orbital. Chlorine has vacant 3d orbital. Electrons jumps from 3s and 3p orbitals to 3d orbitals.