Which of the following polyatomic ions has a 3- ionic charge?

• A. Carbonate, CO_3^{2-}
• B. Phosphate, PO_4^{3-}
• C. Nitrate, NO_3^{-}
• D. Sulfate, SO_4^{2-}

Answer: (B)

Verified step by step guidance

1. Review the given polyatomic ions and their charges: Carbonate (CO_3^{2-}), Phosphate (PO_4^{3-}), Nitrate (NO_3^{-}), and Sulfate (SO_4^{2-}).
2. Recall that the superscript on each ion indicates its ionic charge, where the number represents the magnitude and the sign indicates whether it is positive or negative.
3. Identify the ion with a charge of 3-, which means it has three extra electrons compared to its neutral state, indicated as \(PO_4^{3-}\) for phosphate.
4. Confirm that the other ions have charges of 1- or 2-, such as carbonate (\(CO_3^{2-}\)), nitrate (\(NO_3^{-}\)), and sulfate (\(SO_4^{2-}\)), which do not match the 3- charge requirement.
5. Conclude that phosphate (\(PO_4^{3-}\)) is the polyatomic ion with a 3- ionic charge.