The process requiring the absorption of energy is

Which element has the highest electron gain enthalpy?

To which of the following atoms is the attachment of an electron most difficult?

Assertion $(A)$: Fluorine has a smaller negative electron gain enthalpy than chlorine.
Reason $(R)$: The electron-electron repulsion is higher in chlorine than in fluorine.

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

Fluorine has lower electron affinity than chlorine because of