How will you account for the following? The electron gain enthalpy with negative sign for oxygen (-141 kJ mol^(-1)) is less than that of sulphur (-200 kJ mol^(-1)). Or The value of electron gain enthalpy with negative sign for sulphur is higher than that of oxygen. Or The electron gain enthalpy with sign is less for oxygen than for sulphur.

How will you account for the following? The electron gain enthalpy wi

1.	How will you account for the following? The electron gain enthalpy with negative sign for oxygen (-141 kJ mol^(-1)) is less than that of sulphur (-200 kJ mol^(-1)). Or The value of electron gain enthalpy with negative sign for sulphur is higher than that of oxygen. Or The electron gain enthalpy with sign is less for oxygen than for sulphur.
Answer» Solution :The SIZE of O atom is smaller than that of S. Thus, when an electron is added to neutral gaseous atom, the electon-electron repulsions experienced in the samller 2p-subshell of O are comparatively larger than those encounterned in the bigger 3p-subshell of S. As a result, moreenergy is released in case of S than `{:(O(G)+E^(-) rarr O^(-)(g),,""Delta_(eg) = -141 kJ mol^(-1)),(S(g)+e^(-) rarr S^(-)(g),,""Delta_(eg) = -200 kJ mol^(-1)):}` in case of O. In other words, NEGATIVE electron gain enthalpy of S is higher than that of O.