Question

Why is the first ionization energy of mg greater than al?

Answer 1

Because in Al the valence e- enters in 3p subshell whereas in Mg valence e- enters in 3s subshell............ since the s subshell is more attracted towards the nucleus  so it is not easy to remove e- from a s orbital .............the e- from p orbital can be easily removed as compared to s orbital therfore the 1st ionization enthalpy of Mg is greater than Al