Which element has the highest electron gain enthalpy?

The electron gain enthalpy values (in $kJ \ mol^{-1}$) of three halogens $X$,$Y$ and $Z$ are respectively $-349$,$-333$ and $-325$. Then $X$,$Y$ and $Z$ are respectively

The equation used to represent the electron gain enthalpy is

When a chloride ion is formed from an isolated gaseous chlorine atom,$3.8 \ eV$ of energy is released. This value is equal to the:

The process requiring absorption of energy is

In which of the following processes is energy released?