Question

Which has greater second electron affinity : sulphur or oxygen? why?

Answer 1

Oxygen has greater second electron affinity because Sulfur has 3 shells while oxygen has 2.This increase in shell reduces the nuclear charge and lessens the second I.P.Further Explanation:

Due to the extra shell, the electron in the outermost shell is held , but not as strongly as an oxygen atom has held its electron. So the second Ionization Enthalpy of sulfur will be less than that of Oxygen,because more energy is required to extract the electron from oxygen atom.