Question

The electron gain enthalpy in oxygen family follows:

• A. S > Se > Te > Po > O
• B. S > Se > Te > O > Po
• C. O > S > Se > Te > Po
• D. S > O > Se > Te > Po

Answer 1

The correct option is A S > Se > Te > Po > O

Due to small size of oxygen atom, electrons in small 2p-subshell repel the coming electron more than by 3p-electrons in S. That is why, $E{A}_1$ of O is less than S. On the other hand, on moving from S to Po, the $E{A}_1$ values decreases due to increased size.