What are factors which influence the electron gain enthalpy ?

Explanation

(i) Size of the atom: The new electron which was added experiences .stronger attraction to its nucleus if the atoms are smaller in size.
`"Atomic size" prop(1)/("Electron gain enthalpy")`
Nuclear charge: The new electron which was added experiences stronger attraction to its nucleus if the atom possess greater nuclear charge.
Nuclear charge `prop` Electron gain enthalpy
(iii) Electronic configuration: An atom with stable electronic configuration has no tendency to gain an electron. Such atoms have zero or almost zero electron gain enthalpy.