Question

The order of first electron affinity of O , S and Se :-

(A) O>S>Se (B) S>Se>O (C) Se>O>S (D) S>O>Se

Answer 1

Answer:

Electron affinty decreases down the group, but ‘O’ has small atomic size and 2p-orbital becomes very compact and already has 6 electrons, hence, there is a repulsive force among the already present and added electron, is used to reduce the repulsion. Hence, the E.A of O is less than S, so the order is S > Se > O.