The correct order of the electron gain enthalpy of the given elements is

The increasing order of electron affinity for the given electronic configurations of elements is:
$I$. $1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^5$ $(Cl)$
$II$. $1s^2 \ 2s^2 \ 2p^3$ $(N)$
$III$. $1s^2 \ 2s^2 \ 2p^5$ $(F)$
$IV$. $1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^1$ $(Al)$

The correct electron affinity order is $(EA = -\Delta H_{EG})$

Electron affinity is the

Halogens have maximum negative electron gain enthalpy in the respective periods of the periodic table. Why?

In which of the following processes is energy liberated?