Which statement best explains why magnesium has a larger first ionisation energy than aluminium?
Mg\text{Mg}Mg has a larger nuclear charge than Al\text{Al}Al, which attracts the outer electrons more strongly.
The filled 3s\text{3s}3s subshell in Mg\text{Mg}Mg is stabilized by spin-pair repulsion compared to the 3p\text{3p}3p subshell in Al\text{Al}Al.
The outer electron in Al\text{Al}Al is lost from a 3p\text{3p}3p subshell, which is higher in energy and more shielded than the 3s\text{3s}3s subshell of Mg\text{Mg}Mg.
The outer electron of Al\text{Al}Al is lost from a 3d\text{3d}3d subshell, which has a higher energy than the 3s\text{3s}3s subshell.
