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

Consider the nucleus-electron attraction for a $s$ orbital electron versus a $p$ orbital electron.
Electronic configuration of atomic $M g$: $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2}$, versus $A l$, $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{1}$.
Would you expect it to be easier to remove an electron from a $p$ orbital (with zero electron density at the nucleus), versus an $s$ orbital, which has density at the nucleus? Why?