The formation of the oxide ion `(O_((g))^(2-))` require first an exothermic and then an endothermic step as shown below
`O_((g)) + bar e to O_((g))^(-) , Delta H^(0) = - 142 " kJ mol"^(-)`
`O_((g))^(-) + bar e to O_((g))^(2-) , Delta H^(0) = 844 " kJ mol"^(-)`
This is because

Options

A. Oxygen is more electronegative.
B. `O^(-)`has comparatively larger size than oxygen atom.
C. `O^(-)` ion will tend to resists the addition of another electron.
D. Oxygen has high electron affinity .

Answer

c

Explanation

`O^(-)` ion will tend to resists the addition of another electron.
Addition of second electron is always endothermic because `O^(-)` ion tends to resists the addition of second electron in it.