Question

how many resonance structures can be drawn for no₃⁻? ____

Explanation:

Step1: Draw Lewis structure

First, calculate the total number of valence electrons. Nitrogen (\(N\)) has \(5\) valence electrons, each oxygen (\(O\)) has \(6\) valence electrons, and there is an extra electron due to the \(- 1\) charge. So total valence electrons \(=5 + 3\times6+1=24\).

Step2: Arrange atoms and distribute electrons

Place \(N\) in the center. Connect \(N\) to three \(O\) atoms. Use single bonds first (\(3\) single bonds use \(6\) electrons). Then distribute the remaining \(24 - 6=18\) electrons as lone pairs. Each \(O\) atom gets \(6\) electrons (three lone pairs). But for resonance, we can form double bonds.

Step3: Generate resonance structures

By moving the lone pairs from different \(O\) atoms to form double bonds with \(N\), we can get three resonance structures.

Answer:

\(3\)