Which of the following ions contains a central atom with a formal charge?

• A. NO3^- (nitrate ion)
• B. NH4^+ (ammonium ion)
• C. CO3^{2-} (carbonate ion)
• D. ClO^- (hypochlorite ion)

Answer: (A)

Verified step by step guidance

1. Recall the formula for calculating formal charge on an atom: \(\text{Formal Charge} = \text{Valence Electrons} - \text{Nonbonding Electrons} - \frac{1}{2} \times \text{Bonding Electrons}\).
2. For each ion, identify the central atom and determine its number of valence electrons based on its group in the periodic table.
3. Count the number of nonbonding (lone pair) electrons on the central atom and the number of bonding electrons (shared in bonds) around it.
4. Apply the formal charge formula to the central atom in each ion to calculate its formal charge.
5. Compare the formal charges calculated for the central atoms in all ions; the ion whose central atom has a nonzero formal charge is the correct answer.