Question

Explain why lithium on being heated in air forms the monoxide but not peroxide

Answer 1

Size of lithium is very small thus it has high charge density (positive charge is present on less area) therefore it will highly attract the negative ion of oxide and does not allow oxide ion to combine with another ion while in case of sodium , positive charge is dispersed over larger area , so less effective charge (less effective charge density) and also have larger radii thus it attracts more oxide iona and form peroxide