. What is Electron affinity
1. The amount of energy released when an electron is added to the outermost shell of one mole of an isolated gaseous atom in its lower energy state.
2. Electron affinity just defined is actually first electron affinity since it corresponds to the addition of one electron only. In the process of adding further electron, the second electron will be added to gaseous anion against the electrostatic repulsion between the electron being added and the gaseous anion. Sometimes energy instead of being released is supplied for the addition of an electron to an anion.