Chemistry Question: Correct Chemical Formula for AgZ Compound Explained

[xortan]

If an element Z forms a compound with the formula AgZ, which of the following is a correct chemical formula?

-CaZ₂
-Al₂Z₃
-H₂Z
-NaZ₃

I don't really understand this at all and there is going to be decent amount of them on my final exam! please any help

 

[ideasrule]

Think charges. Since AgZ is an ionic compound, what charge must the Z have? How does this charge tell you whether a certain compound (CaZ2, Al2Z3, etc) is possible?

 

[renob]

CaZ2

Ag ion has a charge of +1 which mean the charge on the Z anion must be -1.

Ca ion has a charge of +2, so it takes two Z anions to bond with it.