Formation of X^(-) ion from 'X' is associated with the release of 144 kJ// mol energy. However, Formation of X^(-2) ion from X^(-) is associated with the absorption of 840 kJ of energy. How do you account for this?

Formation of X^(-) ion from 'X' is associated with the release of 144

1.	Formation of X^(-) ion from 'X' is associated with the release of 144 kJ// mol energy. However, Formation of X^(-2) ion from X^(-) is associated with the absorption of 840 kJ of energy. How do you account for this?
Answer» Solution :During the addition of an electron to a neutral atom, work is done towards the NUCLEAR force of ATTRACTION. HENCE, energy is RELEASED. After the addition of an electron, the uninedative species formed, ltbegt repels the 2ND electron. Hence during the addition of the second electron, work is done against the force of repulsion that requires supply of energy.