State the factors which affect :

(a) electron affinity

(b) electronegativity of elements in a periodic table.

(a) The Factors which affect the electron affinity are:

1. Atomic size — The smaller the atomic size, the greater the electron affinity, because a small atom takes up electrons more readily than a large atom since nucleus has greater attraction on electrons.
2. Nuclear charge — As the nuclear charge increases electron affinity increases because with an increase in nuclear charge the tendency of an atom to accept electrons increases.

(b) The factors affecting electronegativity are:

1. Atomic size — The greater the size of the atom, the lesser the electronegativity because a small atom will pull the shared pair of electrons more than a large atom.
2. Nuclear charge — As the nuclear charge increases electronegativity increases because an increase in nuclear charge increases the force of attraction on the electron.