Which of the following statements correctly describes the Lewis dot structure of the nitrate ion, NO3^-?

• A. It has two resonance structures, each with two double bonds and one single bond to oxygen atoms.
• B. It has three single bonds to oxygen atoms, with no resonance.
• C. It has three equivalent resonance structures, each with one double bond and two single bonds to oxygen atoms.
• D. It has a single structure with two double bonds and one single bond to oxygen atoms.

Answer: (C)

Verified step by step guidance

1. Recall that the nitrate ion, NO3^-, has a total of 24 valence electrons: 5 from nitrogen, 6 from each of the three oxygens (3 × 6 = 18), plus 1 extra electron due to the negative charge, totaling 5 + 18 + 1 = 24 electrons.
2. Draw a skeletal structure with nitrogen in the center bonded to three oxygen atoms. Initially, connect each oxygen to nitrogen with a single bond.
3. Distribute the remaining valence electrons to satisfy the octet rule for the oxygen atoms first, then place any leftover electrons on the nitrogen atom.
4. Recognize that the nitrate ion exhibits resonance because the double bond can be placed between nitrogen and any one of the three oxygen atoms, resulting in three equivalent resonance structures.
5. Understand that each resonance structure has one N=O double bond and two N–O single bonds, and the actual structure is a resonance hybrid where all N–O bonds are equivalent and have partial double bond character.