Question

Write an equation that shows the formation of the oxide ion from a neutral oxygen atom.

_________________ + __________________ --------------->_______________+__________________

Answer 1

Neutral oxygen atom has six electrons in the valence shell. It gains two electrons in a chemical reaction thus forming the oxide anion O^2-. The reaction can be written as

O + 2 e^- --------------> O^2-

Since oxide ion has 2 extra electrons in its valence shell, the charge on the ion is negative.

If you want to know how this plays out in a reaction, take the example of lithoum oxide Li₂O. The two lithium atoms will loose one electron each to form Li⁺ ion. These two electrons from 2 Li atoms are accepted by the oxygen atom to form O^2- (oxide) ion. Li⁺ ion and O^2- ion form an ionic bond between them due to elctrostatic attraction and form Li₂O (lithium oxide).