The formation of the oxide ion `O^(2-)` (g) requires first an exothermic and then an endothermic step as shown below,
`O(g)+ e^(-) = O^(-)(g), DeltaH^(@)= -142kJmol^(-1)`
`O^(-)(g) +e^(-) =O^(2-)(g), DeltaH^(@)= 844 kJmol^(-1)`
This is because : oxygen is more electronegative, oxygen has high electron affinity, `O^(-)` ion will tend to resist the addition of another electron , ` O^(-)` ion has comparatively larger size than oxygen atom

Options

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

Answer

C

Explanation

`O^-` ion will tend to resist the addition of another electron