Question

what is electron affinity definition

Answer 1

Electron affinity basically means the amount of energy given out when an electron is accepted by an isolated gaseous atom.
It can be understood as the tendency of an atom to accept electron in its outermost shell while if you get confused with electronegativity then it is the tendency of an atom to attract it toward itself.
Chlorine has the highest electron affinity and Flourine has the highest electronegativity.

Answer 2

The amount of energy released when an electron is added to the valence shell of neutral gaseous atom.......
This is electron enthalpy..
Hope it helps.....