The enthalpy of ionization of magnesium refers to the energy required to remove one electron from a magnesium atom to form a magnesium ion Mg . In this case, we are given the first ionization energy of Mg, which is the energy required to remove one electron from a magnesium atom to form a Mg ion. However, we need to find the energy required to remove a second electron to form a Mg ion.Unfortunately, the given data lattice energy of MgCl is not directly related to the ionization energy of magnesium. The lattice energy of MgCl is the energy released when one mole of solid MgCl is formed from its gaseous ions Mg and 2Cl . To find the enthalpy of ionization of magnesium Mg Mg + 2e , we need the second ionization energy of Mg. The first ionization energy is given as 738 kJ/mol, and the second ionization energy of Mg is approximately 1450 kJ/mol.Now, we can calculate the enthalpy of ionization of magnesium:Enthalpy of ionization = First ionization energy + Second ionization energyEnthalpy of ionization = 738 kJ/mol + 1450 kJ/molEnthalpy of ionization = 2188 kJ/molSo, the enthalpy of ionization of magnesium is 2188 kJ/mol.