First electron affinity for oxygen is exothermic but second electron affinity for oxygen is endothermic explain - Science - Periodic Classification of Elements

Question

First electron affinity for oxygen is exothermic but second
electron affinity for oxygen is endothermic explain

Geetha · Accepted Answer

Electron affinity is the energy change in an atom when an electron is added to a neutral gaseous atom
In oxygen O + e-  → O-First EA = -142 kJ/molThe first electron affinity is negative showing its exothermic, energy is released during the addition of electron to the neutral atom
 O- + e- → O2-Second EA = + 844 kJ/molThe second reaction is endothermic showing that energy is absorbed to perform this change
The second electron affinity of oxygen is high because the electron is added forcefully to a small, very dense space
 As well as its added to an already negative ion

First electron affinity for oxygen is exothermic but second electron affinity for oxygen is endothermic.explain