[jupiter_8917]

Write the correct chemical formula for the compounds formed from each pairs of ions.

a. K+, S^2-
b. Ca^2+, O^2-
c. Na+, O^2-
d. Al^3+, N^3-

Is it related to octet rule, can anyone please explain to me how to do those problems??? Thank you!!!

[enahs]

You are trying to form a compound, an uncharged species.
It is just basic math.
A) If you have one something with 2 negative charges, how many of the other things with a 1 positive charge do you need to make the compound neutral?

[Floreaa]

The compound is uncharged, so the charges of the ions all added together must give 0 as a result. So for the firs compound you have 2 negative charges. What amount of electric curent wil be needed to make the over all charge of the compound 0. Of course +2. You know that the K⁺ has the electro-valence +1 so You will need 2 K⁺ ions. The compound will be: K₂S

The rest are solved in the same way:

• CaO
• Na₂O
• AlN

[Borek]

What amount of electric curent wil be needed to make the over all charge of the compound 0. Of course +2.

While you are to some extent correct in your analysis, terms you are using make me dizzy. There is no such thing as "amount of electric current equal +2". Current is current, charge is charge, these are completely different (although related) things.

[Floreaa]

What amount of electric curent wil be needed to make the over all charge of the compound 0. Of course +2.

I indeed made a mistake and put together two different concepts: electric charge and electric current. Sorry for that! In reality we are of course talking of charge not current.