Question

Electron gain enthalpy of chlorine is more negative value as compared to that of fluorine (F). Why?

Answer 1

Fluorine is highly electronegative. It has a great affinity for the electrons but is not capable of being stable by taking an electron. Wheareas Chlorine has its vaccant d orbitals to give enough vaccancy for the electrons & to be stable. Thus, electron gain enthalpy that denotes stability after gaining electron is higher for the Chlorine than for the Fluorine.