The ionization energy of F− is 320 kJ/mole. The electron gain enthalpy of fluorine would be?
-320 kJ/mole
Ionization enthalpy is exactly opposite to electron gain enthalpy in this case. If you are talking about ionization enthalpy of F and electron gain enthalpy of F, then we can't say the same thing.
F−⟶ F + e− ΔH = 320kJ/mole(I.E)
F+e−⟶ F− ΔH = −320kJ/mole(I.E)