Question

Which has lower elecron gain enthalpy and why (florine or chlorine)?

Answer 1

Hey mate here's your answer

The negative electron gain enthalpy of fluorine is less than that of chlorine. It is due to small size of fluorine atom. As a result, there are strong interelectronic repulsions in the relatively small 2p orbitals of fluorine and thus, the incoming electron does not experience much attraction.