Question

Electron affinity of the element or ions is correctly shown in :

• A. $S>O^{-}$
• B. $O>S^{-}$
• C. $S>O$
• D. $N^{-}>S$

Answer 1

Answer: (A), (B), (C)

$S>O$

The electron gain enthalpy of negatively charged species is endothermic.
Hence $O^{-}$ and $S^{-}$ will have positive gain enthalpy due to inter electron repulsions between incoming electron and negatively charged species. Hence ,

$S>O^{-}$ and $O>S^{-}$

Due to high charge density, electron affinity of $S$ is greater than $O$.