Question

Out of f and o which has more negative electron gain enthalpy and why

Answer 1

F (fluorine) have more negative electron hain enthalpy as it needs only one electron to complete its valancy while oxygen needs 2 electrons to completely fill its orbital.

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.