Which of the following are the values of electron affinities in kJ/mol for the formation of O– and O2– from O ?

O(g) + e- → O-(g)   ΔH = -141 KJO(g) + 2e-→ O2-(g ) ΔH =+702 KJThe negative charge of O-(g) repels the incoming electron and thus O-(g) →O-2 is endothermic.Note that endothermic  nature of 2nd electron gain enthalpy is greater than exothermic nature of 1st electron gain enthaply.