Question

Why is the first ionization energy of aluminum lower than the first ionization energy of magnesium?

Answer 1

because:

☸ electronic configuration of Mg= 1s2 2s2 3s2
which is having fully filled s-orbital and hence is more stable

☸ electronic configuration of Al=1s2 2s2 3s2 4p1
so... here... we have 1p electron... which can be easily removed...

☸this is so because half filled and fully filled electronic configuration are more stable

☸hence...first ionisation enthalpy of Mg is higher than Al

hope it helps you..
☺☺

Answer 2

here is your ans ....i think it's will help u..