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

• A. SO_2^{2-}
• B. SO_3^{2-}
• C. SO_4^{2-}
• D. S_2O_3^{2-}

Answer: (C)

Verified step by step guidance

1. Understand that the sulfate ion is a polyatomic ion composed of sulfur and oxygen atoms with a specific charge.
2. Recall the common polyatomic ions involving sulfur and oxygen: sulfite (SO_3^{2-}), sulfate (SO_4^{2-}), and others like thiosulfate (S_2O_3^{2-}).
3. Identify the number of oxygen atoms and the charge associated with each ion: sulfite has 3 oxygens and a 2- charge, sulfate has 4 oxygens and a 2- charge, thiosulfate has 3 oxygens, 2 sulfurs, and a 2- charge.
4. Recognize that the sulfate ion specifically has the formula \(SO_4^{2-}\), meaning one sulfur atom bonded to four oxygen atoms with an overall charge of 2-.
5. Conclude that among the given options, \(SO_4^{2-}\) is the correct formula for the sulfate ion.