Howwouldyouexplain the fact that the first ionization enthalpy of sodium islower than that of magnesium but its second ionization enthalpy is higher thanthat of magnesium?

Howwouldyouexplain the fact that the first ionization enthalpy of sodi

1.	Howwouldyouexplain the fact that the first ionization enthalpy of sodium islower than that of magnesium but its second ionization enthalpy is higher thanthat of magnesium?
Answer» Valence shell electronic configuration of Na is 3s1 and of Mg is 3s2The first electron is to be removed from ha;lf filled 3s orbital of Na which is more easy as compare to the removal of one electron from fully filled stable 2s orbital of Mg. So,first ionization enthalpy of sodium is lower than that of magnesium .The 2ndelectron is to be removed from fully filled 2p orbital of Na+ which requires extra energy as compare to removal of electron from half filled 2s orbital of Mg+.So,second ionization enthalpy of Na is higher than that of magnesium.