Question

Electron affinity is positive, when

• A. $O $ changes into $O^{-}$
• B. $O^{-} $ changes into $O^{2-}$
• C. $O$ changes into $O^{+}$
• D. electron affinity is always negative

Answer 1

The Correct Option is B

When $O ^{-}$, changes into $O ^{2-}$, change is endothermic because $O ^{-}$repels the incoming electron due to similar charge, hence it needs energy to accept the electron. So, electron affinity is positive.