Ionization Enthalpy is defined as the amount of energy required to remove an atom's electron (can be valence or consecutive) - Chemistry -

Question

Ionization Enthalpy is defined as the amount of energy required
to remove an atom's electron (can be valence or consecutive) this
definition doesn't sound so complex The definition of Electron Gain
Enthalpy - it is the amount of energy required to add an electron
But, what is Electron Affinity ? One book says it is the negative
of electron gain enthalpy Then, there is some thermodynamic rule
saying negative value of electron gain enthalpy indicates that
energy has to be supplied and positive value indicates energy is
released My question is how can electron gain enthalpy have both
negative and positive values but ionisation enthalpy doesn't have
Also please explain what the differnece between affinity and gain
enthalpy is Thanks in advance

Anjali Babhulkar · Answer

​Electron Gain Enthalpy is the energy released when one mole
ofelectron are added to gaseous atoms of an element Electron
Affinity is the same as Electron Gain Enthalpy but viewed as the
energy supplied to the surroundings rather than that released by
the atoms