The second electron affinity of an element 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:

Electronic configurations of four elements $A, B, C$ and $D$ are given below :
$(A)$ $1s^2 2s^2 2p^6$
$(B)$ $1s^2 2s^2 2p^4$
$(C)$ $1s^2 2s^2 2p^6 3s^1$
$(D)$ $1s^2 2s^2 2p^5$
Which of the following is the correct order of increasing tendency to gain electron :

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 $kJ$?

Which of the following represents the correct order of increasing electron gain enthalpy (with negative sign) for the elements?
$a.$ Nitrogen
$b.$ Phosphorus
$c.$ Chlorine
$d.$ Fluorine

The correct order of electron affinity of $B, C, N, O$ is