What is the difference between electron gain enthalpy an electron affinity?
The Electron affinity of an atom or molecule is defined as the amount of energy released when an electron is added to a neutral atom or molecule to form a negative ion.
X + e? ? X?
Electron gain enthalpy is the amount of energy released when an isolated gaseous atom accepts an electron to become a monovalent gaseous anion.
eq:atom(gas) +electron → anion(gas) +energy(electron gain enthalpy)