Would you expect the second electron gain enthalpy of `S` as positive, more negative or less negative than the first? Justify your answer.

Answer

The second electron gain enthalpy of `S` is positive as explained below: When an electron is added to `S` atom to form `S^(-)` ion, energy is released. Thus, first electron gain enthalpy of `S` is negative.
`S(g) +e^(-)(g) rarr S^(-) (g); Delta_(eg)H =- 200.4 kJ mol^(-1)`
But when another electron is added to `S^(-)` to from `S^(2-)` ion, energy is absorbed to overcome the strong electrostatic repulsion betwene the negatively charged `S^(-)` ion and the second electron being added. Thus, the second electron gain enthalpy of sulphur is positive.
`S^(-) (g) +e^(-)(g) rarr S^(2-) (g); DeltaH_(eg)H = + 532 kJ mol^(-1)`