Which of the following is the correct chemical formula for the nitrite ion?

• A. NO_3^-
• B. N_2O_2^-
• C. NO_2^-
• D. NO_2^+

Answer: (C)

Verified step by step guidance

1. Understand that the nitrite ion is a polyatomic ion composed of nitrogen and oxygen atoms with a specific charge.
2. Recall the common polyatomic ions involving nitrogen and oxygen: nitrate (NO_3^-), nitrite (NO_2^-), and others like nitronium (NO_2^+).
3. Identify that the nitrite ion specifically has one nitrogen atom and two oxygen atoms, carrying a single negative charge.
4. Compare the given options to this definition: NO_3^- has three oxygens (nitrate), N_2O_2^- has two nitrogens and two oxygens, NO_2^- has one nitrogen and two oxygens with a negative charge, and NO_2^+ has a positive charge.
5. Conclude that the correct formula for the nitrite ion is \(NO\_2^-\) because it matches the composition and charge of the nitrite ion.