1) ZnSO4 would it be Zn(SO4)

does the polyatomic ion always have to have ( ) ?

2) Is Ba(SO4) right?
since Ba is 2+ and SO4 is 2- right?

3) In a net ionic equation for BaCI2 would it become Ba ^(2+) + 2CI or Ba ^(2+) + CI2 ?

For #2 did I write it correctly?

Also would Sr3(PO4)2 be right?

1) ZnSO4 would it be Zn(SO4)

does the polyatomic ion always have to have ( ) ?
Parentheses are required ONLY when the subscript for SO4 is not 1. In ZnSO4 the parentheses are not needed.

2) Is Ba(SO4) right?
since Ba is 2+ and SO4 is 2- right?
Yes, Ba(SO4) is right but the parentheses are not needed.

3) In a net ionic equation for BaCI2 would it become Ba ^(2+) + 2CI or Ba ^(2+) + CI2
I think you mean BaCl2 (barium chloride) since I am not familiar with CI2. The ionization of BaCl2 is to Ba^+2 and 2Cl^-

Cl is chlorine. That is a "see""ell" and not a "see""eye".

1) To determine the correct formula for a compound, like ZnSO4, we need to consider the charges of the individual ions involved. ZnSO4 consists of the zinc cation (Zn^2+) and the sulfate anion (SO4^2-). The formula should accurately represent the ratio of ions in the compound.

The ion Zn^2+ has a charge of +2, while the sulfate ion (SO4^2-) has a charge of -2. To balance the charges, we need two sulfate ions for every zinc ion. This means the correct formula for zinc sulfate is Zn(SO4)2.

Regarding your question about polyatomic ions, using parentheses is not mandatory when writing formulas. However, using parentheses can help clarify the ratio of ions in the compound, especially when there are multiple polyatomic ions present.

2) Ba(SO4) is indeed correct for barium sulfate. Barium (Ba) has a charge of 2+ (Ba^2+), while sulfate (SO4) has a charge of 2- (SO4^2-). To balance the charges, we need one barium ion for every sulfate ion. Therefore, the formula Ba(SO4) correctly represents this compound.

3) The net ionic equation for the dissociation of BaCl2 should be:
BaCl2(s) → Ba^2+(aq) + 2Cl^-(aq)

In the net ionic equation, we only include the species that are actually undergoing a chemical change, leaving out any spectator ions. In this case, the solid BaCl2 dissociates into aqueous Ba^2+ ions and chloride (Cl^-) ions.

Note that CI2 refers to chlorine gas, which is not the correct representation for the chloride ion (Cl^-). The correct formula for the chloride ion is simply Cl^-.