# Question #cd842

To form sodium chloride (table salt) the positive sodium cation has a charge of $N {a}^{- 1}$ and the chlorine has a charge of $C {l}^{- 1}$.
In the case of aluminum oxide, the $A {l}^{+ 3}$ cation and the ${O}^{- 2}$ will balance at $A {l}_{2} {O}_{3}$ because the two aluminum ions will create a +6 charge and the three oxide ions will create a -6 charge making them equal and opposite with a total charge of zero or neutral.