Which of the following is the correct formula for the sulfate ion, a common polyatomic ion?

• A. SO_4^{2-}
• B. SO_3^{2-}
• C. NO_3^{-}
• D. CO_3^{2-}

Answer: (A)

Verified step by step guidance

1. Understand that the problem asks for the correct chemical formula of the sulfate ion, which is a common polyatomic ion.
2. Recall that polyatomic ions are charged species composed of multiple atoms covalently bonded together, carrying an overall charge.
3. Identify the sulfate ion by its known chemical formula, which consists of one sulfur atom and four oxygen atoms, with an overall charge of 2-.
4. Write the formula for sulfate ion using proper notation: \(SO_4^{2-}\), where the subscript 4 indicates four oxygen atoms and the superscript 2- indicates the charge.
5. Compare the given options to confirm that \(SO_4^{2-}\) matches the sulfate ion, while the others represent different ions (e.g., sulfite \(SO_3^{2-}\), nitrate \(NO_3^{-}\), carbonate \(CO_3^{2-}\)).