Question

electron gain enthalpy of cl is higher than that of f

Answer 1

Flourine,due to its small size cannot accept one more electron into its p orbital i.e its electron repulsion energy is more but chlorine, due to its larger atomic size have no trouble in accepting the electron.Therefore the electron gain enthalpy is more for chlorine than flourine.

Answer 2

Answer:

Due to its small size, the electron–electron repulsions in the relatively compact 2p-sub-shell are comparatively large, and hence, the incoming electron is not accepted with the same ease as is the case with larger Cl atom. Consequently, electron gain enthalpy of Cl is more negative than that of F.