Electron affinity It is the amount of energy given out when an electron is added to a neutral gaseous atom. This results in the formation of an anion. For example Cl + e– → Cl + energy. The electron affinity of chlorine is 348 kJ mol-1. Electron affinity changes across a period. The electron affinity
Ionization energy (or potential) of an element is defined as “The amount of energy required or needed to remove an electron from the neutral gaseous atom to form unipositive ion , for example Na → Na+ + e– + energy This is measured in electron volts per atom or kJ mol-1. For example IE of
Quantization: means that a quantity does not vary continuously. The energy of an electron in an atom cannot have any arbitrary value but only certain characteristic values. A definite quantum of energy is accepted while moving from lower to higher energy level or lost while moving from higher to lower energy level, It does not