The first ionization enthalpies of Na, Mg and Si are respectively 496, 737 and 786 kJ mol^-1. What would be the first ionization enthalpy of Al in kJ mol^-1 ?

The atomic number of Al is 13 and its electronic configuration of Al is 1s² 2s² 2p⁶ 3s² 3p¹. The first Ionization enthalpy of Al is less than Mg because Mg has a filled stable configuration but less than Na (as Na is a highly positive metal). So, the value of Al is less than Mg but greater than Na. So, the first ionization energy of Al is around 575 kJ/mol.