Question

which of the following will have the most negative electron gain enthalpy and which has the least negative value?
P, S, Cl and F. Justify your choice.

Answer 1

We know,Halogens have highest negative value of electron gain enthalpy. Here Cl and F both are halogens but electron gain enthalpy of Cl is more negative than F because of very small size of F which causes interelectronic repulsion among its electrons.
Cl has the most negative one.
P has the less negative one due to larger size.