To calculate the enthalpy change for the ionization of magnesium, we need to consider both the first and second ionization energies. The enthalpy change for the ionization process is the sum of the first and second ionization energies.Enthalpy change = First ionization energy + Second ionization energyEnthalpy change = 738 kJ/mol + 1450 kJ/molEnthalpy change = 2188 kJ/molThe enthalpy change for the ionization of magnesium is 2188 kJ/mol.