Which resonance structure is likely to contribute most to the correct structure of N_2O?

• A. N–N≡O with a negative formal charge on the terminal nitrogen and a positive formal charge on oxygen
• B. N≡N–O with a negative formal charge on oxygen and a positive formal charge on the terminal nitrogen
• C. N=N=O with all atoms neutral and no formal charges
• D. N≡O–N with a negative formal charge on the central nitrogen and a positive formal charge on oxygen

Answer: (B)

Verified step by step guidance

1. Step 1: Understand that resonance structures are different Lewis structures for the same molecule that differ only in the placement of electrons, not atoms. The most significant resonance contributor is the one with the lowest formal charges and the most stable arrangement of charges.
2. Step 2: Calculate the formal charges for each atom in the given resonance structures using the formula: \(\text{Formal charge} = \text{Valence electrons} - (\text{Nonbonding electrons} + \frac{1}{2} \times \text{Bonding electrons})\).
3. Step 3: Evaluate each resonance structure by checking if the formal charges are minimized and if negative formal charges reside on the more electronegative atoms (oxygen is more electronegative than nitrogen). Structures with formal charges closer to zero and negative charges on more electronegative atoms are more stable.
4. Step 4: Compare the resonance structures: the one with \(\mathrm{N \equiv N - O}\) having a negative formal charge on oxygen and a positive formal charge on the terminal nitrogen aligns with the electronegativity considerations and formal charge minimization.
5. Step 5: Conclude that the resonance structure with \(\mathrm{N \equiv N - O}\), negative charge on oxygen, and positive charge on terminal nitrogen contributes most to the correct structure of \(\mathrm{N_2O}\) because it best satisfies the rules for resonance stability.