Which of the following is the correct formula for the sulfate ion?

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

Answer: (C)

Verified step by step guidance

1. Identify the sulfate ion by its chemical formula and charge. The sulfate ion consists of one sulfur atom and four oxygen atoms, carrying an overall charge of 2-.
2. Recall the general notation for polyatomic ions, where the element symbols are followed by the charge in superscript, for example, \(SO_4^{2-}\).
3. Compare the given options: \(CO_3^{2-}\) is carbonate, \(NO_3^{-}\) is nitrate, \(SO_4^{2-}\) is sulfate, and \(SO_3^{2-}\) is sulfite.
4. Understand that the sulfate ion has four oxygen atoms and a 2- charge, which matches the formula \(SO_4^{2-}\).
5. Conclude that the correct formula for the sulfate ion is \(SO_4^{2-}\) based on its composition and charge.