Which of the following Lewis structures for the nitrate ion (NO_3^-) has the formal charges correctly assigned?

• A. Central N: +1; each O: -1
• B. Central N: -1; each O: 0
• C. Central N: 0; each O: -1
• D. Central N: 0; one O: -1; two O: 0

Answer: (D)

Verified step by step guidance

1. Recall that the nitrate ion (NO_3^-) consists of one nitrogen atom centrally bonded to three oxygen atoms, with an overall charge of -1.
2. Draw the Lewis structure for NO_3^- by placing nitrogen in the center and connecting it to three oxygens with single bonds initially, then add double bonds as needed to satisfy the octet rule and minimize formal charges.
3. Calculate the formal charge for each atom using the formula: \(\text{Formal Charge} = \text{Valence Electrons} - \text{Nonbonding Electrons} - \frac{1}{2} \times \text{Bonding Electrons}\).
4. Assign formal charges to nitrogen and each oxygen based on the Lewis structure, remembering that the sum of all formal charges must equal the overall charge of the ion (-1).
5. Compare the formal charges you calculated with the given options to identify the correct assignment: nitrogen with zero formal charge, one oxygen with -1, and the other two oxygens with zero formal charge.