Question

Why is electron gain enthalpy also positive when a monovalent anion is changed to divalent anion?​

Answer 1

Explanation:

When one electron is added to an atom, it becomes negatively charged ions. Now if we add the second electron to this negatively charged ion, it experiences repulsive forces due to the electrons already present in that shell. ... Hence, the second electron gain enthalpy of an element is positive.