The flame colours of metals ions are due to

Options

(a) Frenkel deffect
(b) Schottky defect
(c) Metal deficiency defect
(d) Metal excess defect

Correct Answer:

Metal excess defect

Explanation:

The flame colours of metal ions are due to metal excess defect. These type of crystals are generally coloured.This is due to the presence of free electrons. These electrons get excited easily to higher energy levels by absorption of certain wave lengths from the visible light and therefore, the compounds appear coloured.