Question

Arrange N, O and S in order of decreasing electron affinity:

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

Answer 1

The correct option is A $S>O>N$

Electron affinity increases as you add more valence electron. That puts oxygen $\left(O\right)$ as having more electron affinity than $\left(N\right)$. So, $O>N$

Electron affinity would typically decrease as you move down the periodic table.

But there is a factor in the second period of elements due to the close distance or the orbital from the nucleus so that repulsion of an electron from each other reduce electron affinity.

So, $S>O>N$