On exposure to air, alkali metals get tarnished due to formation of oxides, hydroxides and carbonates on their surface. When heated in air or oxygen they burn vigorously forming different types of oxides depending upon the nature of the metal. The formation and stability of these metals can be explained on the basis of size of alkali metal ion and the anion. Peroxides are colourless, while superoxides are coloured. The normal oxides are basic while peoxides and superoxides act as oxidising agents On heating in excess of oxygen, lithium gives

On exposure to air, alkali metals get tarnished due to formation of ox

1.	On exposure to air, alkali metals get tarnished due to formation of oxides, hydroxides and carbonates on their surface. When heated in air or oxygen they burn vigorously forming different types of oxides depending upon the nature of the metal. The formation and stability of these metals can be explained on the basis of size of alkali metal ion and the anion. Peroxides are colourless, while superoxides are coloured. The normal oxides are basic while peoxides and superoxides act as oxidising agents On heating in excess of oxygen, lithium gives
Answer» `Li_(2)O` LIO `Li_(2)O_(2)` `LiO_(2)` Solution :On heatingin EXCESS of air LI forms OXIDE `4Li+O_(2)rarr2Li_(2)O_(s)`