Question

Calculate the enthalpy change for the ionization of magnesium, given that it requires 738 kJ/mol to remove an electron from a gaseous magnesium atom, and that the ionization energy for a second electron is 1450 kJ/mol.

Answer 1

To calculate the enthalpy change for the ionization of magnesium, we need to consider both ionization steps. Magnesium has two valence electrons, so it will lose both electrons to form a Mg ion.The first ionization energy is given as 738 kJ/mol, which corresponds to the removal of the first electron:Mg g   Mg g  + e    H = +738 kJ/molThe second ionization energy is given as 1450 kJ/mol, which corresponds to the removal of the second electron:Mg g   Mg g  + e    H = +1450 kJ/molTo find the total enthalpy change for the ionization of magnesium, we need to add the enthalpy changes for both ionization steps:H_total = H + HH_total =  +738 kJ/mol  +  +1450 kJ/mol H_total = +2188 kJ/molSo, the enthalpy change for the ionization of magnesium is +2188 kJ/mol.