The value of $2^{nd}$ electron gain enthalpy for $O$ and $S$ will be (in $kJ/mol$)

The formation of the oxide ion,$O^{2-}_{(g)}$,from oxygen atom requires first an exothermic and then an endothermic step as shown below:
$O_{(g)} + e^- \to O^{-}_{(g)} ; \Delta_f H^{\Theta} = -141 \ kJ \ mol^{-1}$
$O^{-}_{(g)} + e^- \to O^{2-}_{(g)} ; \Delta_f H^{\Theta} = +780 \ kJ \ mol^{-1}$
Thus,the process of formation of $O^{2-}$ in gas phase is unfavourable even though $O^{2-}$ is isoelectronic with neon. It is due to the fact that,

Identify the set of elements in which they are arranged in the increasing order of electron gain enthalpies.

If the electron affinity of $Cl$ is $348 \ kJ/mol$,then how much energy is released to convert $1.0 \ g$ of $Cl$ into $Cl^-$ gas in $kJ$?

For the process
$A_{(g)} + e^- \to A^{-}_{(g)};$ $\Delta H = x$
and $A^{-}_{(g)} \to A_{(g)} + e^-;$ $\Delta H = y$
Select the correct statement:

Which of the following elements will have the lowest electron affinity?