Question

Explain the various factors that affect electron affinity.

Answer 1

Electron affinity mainly depend on three factors. They are,

1. Atomic size
2. Nuclear charge
3. Electronic configuration

• Atomic size $\to$ If the size of the atom is more, greater will be the distance between nucleus and incoming electron. Hence the incoming electron experiences less forces of attraction towards the nucleus of an atom. Therefore, smaller will be electron affinity value.
• Nuclear charge $\to$ If the nuclear charge increases, the attraction for the incoming electron increases. Hence the electron affinity value increases.
• Electronic configuration $\to$ Atoms with stable electronic configuration have a less tendency to accept an electron. Hence they possess smaller electron affinity values.

$\star$ Note:- Electron affinities are low or almost zero in elements having stable electronic configurations (half filled and completely filled valence subshells) because of the small tendency to accept additional electron.