Question

why electron gain enthalpy of sulphur more negative than oxygen

Answer 1

Electron gain enthalpy of sulphur is less than oxygen, as down the group e-gain enthalpy decreases.

Answer 2

sulphur has more negative electron gain enthalpy than oxygen bcoz oxygen has relatively small size than sulphur and hence oxygen cannot accomodate more electons and to do so we need to provide extra energy and providing extra energy means more positive electron gain enthalpy

the energy relesed by sulphur is more than that of oxygen to while accepting an electron

when energy is released we say that the enthalpy is negative

more the energy is released more negative is the electron gain enthalpy

oxygen is more electronegative than sulphur therefore the energy reqired to be released is lesser

or we can say that...

                    Oxygen does not have a d-orbital, but sulphur has a d-orbital. So, oxygen is not able to accommodate more electrons due to its small size showing more electron repulsion. Whereas sulphur has plenty of space in the d-orbital and has comparatively lesser electron repulsion.

Hope  this  may  help  you  and  be  the  brainliest....