The charge on aluminum when it forms an ion would be +3
The charge that the atom of an element carries depends on the number of valance electrons in its outermost shell and whether it is more likely to gain or lose electrons to achieve a stable state.
Aluminum atom has 3 valence electrons in its outermost shell. It either gains 5 more or donates the 3 valence electrons in order to achieve an octet state. Since it is easier to donate 3 than gain 5, the atom of aluminum will prefer to donate the 3 valence electrons to become stable.
Thus, the aluminum atom will form an ion by carrying +3 charge.
More on ion formation can be found here: https://brainly.com/question/305470?referrer=searchResults
