Question
Question: The correct order of electron gain enthalpy (- ve value) is :...
The correct order of electron gain enthalpy (- ve value) is :
A
O > S > Se > Te
B
O < S < Se < Te
C
O < S > Se > Te
D
O < S > Se < Te
Answer
O < S > Se > Te
Explanation
Solution
Electron gain enthalpy generally becomes less negative down a group. However, in Group 16, Oxygen has a more negative electron gain enthalpy than Sulfur due to electron-electron repulsion in Oxygen's compact 2p orbitals. The order of magnitudes is: |S| > |Se| > |Te| > |O|. This corresponds to the inequality O < S > Se > Te.