Answer:
1. +3.
2. 2 atoms each one loses 3.0 electrons and bonded to 3 O atoms (each one gain 2 electrons).
Explanation:
If every oxygen ion (combined with an aluminum ion) has a charge of -2,
1. what must the charge of each aluminum ion be? How can you tell this?
The charge of each Al ion is +3.
The Al₂O₃ is neutral. the formal charge of the molecule is zero.
∴ 2(charge of Al) + 3(charge of oxygen) = 0.
2(charge of Al) + 3(- 2) = 0.
2(charge of Al) - 6 = 0.
2(charge of Al) = + 6.
(charge of Al) = +6/2 = +3.
2. Also, what has to happen to an uncharged aluminum atom so that it will bond with oxygen?
Al is a metal that has the tendency to lose electrons and oxygen has the tendency to gain electrons.
So, 2 atoms each one loses 3.0 electrons and bonded to 3 O atoms (each one gain 2 electrons).