Question

The correct order of electron affinity among the following species:
$O,S,Se$

• A. $O>S>Se$
• B. $S>Se>O$
• C. $Se>S>O$
• D. $O>Se>S$

Answer 1

The correct option is B $S>Se>O$

As the electron affinity decreases down the group due to increase in number of shells. The order of electron affinity should be: $O>S>Se$.
But as the oxygen have small size and high electron density so electron affinity of $O$ becomes less than $S$ and $Se$.
So the correct order of electron affinity is: $S>Se>O$.