Question

Everything is neutral. Touch a table, a chair, a desk, a tree, and you don't get a shock. Compounds are neutral. So Al2O3 must be neutral. Al has a valence of +3. Oxygen has a valence of -2. Now, let's add the charges.
2 Al @ +3 each is +6.
3 O @ -2 each is -6.
So we have 6 + charges and 6 - charges. They add to zero. Another example.

NaCl. Na is +1. Cl is -1.
Those add to zero.




can anyone help?

aliminium oxide AI2O3, how do they come to this formula when Aliminium has a valency of +3 and oxygen has a valency of -2?

Please help :)