Question

The electron gain enthalpies of halogens in $kJmo{l}^{-1}$ are as given below:
F = $-332$, Cl = $-349$, Br = $-324$, I = $-295$.
The less negative value for F as compared to that of CI is due to:

• A. Strong electron-electron repulsion in the compact 2p- sub shell of F.
• B. Weak electron - electron repulsion in the bigger 3p- sub shell of Cl
• C. Smaller electronegativity value of F than Cl
• D. (A) and (B) both

Answer 1

The correct option is D (A) and (B) both

Due to small size of F atom, the electron-electron repulsion in compact 2p- sub shell is large and hence, the incoming electron is not accepted with the same ease as in the case with Cl (less electron - electron repulsion)