Which of the following correctly pairs the polyatomic ion with its formula?

• A. Ammonium — NH_4^{+}
• B. Nitrate — NO_2^{-}
• C. Sulfate — SO_4^{2-}
• D. Phosphate — PO_3^{3-}

Answer: (C)

Verified step by step guidance

1. Review the common polyatomic ions and their correct chemical formulas, focusing on the charge and the number of atoms in each ion.
2. Recall that Ammonium is a positively charged ion with the formula \(NH_4^{+}\), meaning it contains one nitrogen atom and four hydrogen atoms with a +1 charge.
3. Understand that Nitrate is a negatively charged ion with the formula \(NO_3^{-}\), which has one nitrogen atom and three oxygen atoms with a -1 charge; note that \(NO_2^{-}\) corresponds to Nitrite, not Nitrate.
4. Recognize that Sulfate is a negatively charged ion with the formula \(SO_4^{2-}\), consisting of one sulfur atom and four oxygen atoms with a -2 charge.
5. Know that Phosphate is a negatively charged ion with the formula \(PO_4^{3-}\), containing one phosphorus atom and four oxygen atoms with a -3 charge; \(PO_3^{3-}\) is not the correct formula for Phosphate.