Which of the following represents the correct order of electron affinity?

The second electron gain enthalpy of an element:

Explain the periodicity of electron gain enthalpy of elements in the periodic table.

Which of the following arrangements for the three halogens $Cl$,$Br$,and $I$ when placed in the order of their increasing electron affinity is correct?

Which halogen has the highest value of negative 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