Which of the following is the correct Lewis dot structure for the neutral compound HCNO?

• A. H–C=N=O with a lone pair on C
• B. H–C≡N–O with a lone pair on O
• C. H–C–N=O with a lone pair on N
• D. H–C=N–O with a lone pair on N

Answer: (B)

Verified step by step guidance

1. Step 1: Determine the total number of valence electrons for the molecule HCNO. Add the valence electrons from each atom: H (1 electron), C (4 electrons), N (5 electrons), and O (6 electrons).
2. Step 2: Arrange the atoms in a plausible connectivity. Since hydrogen typically forms only one bond, it will be bonded to carbon. The remaining atoms (C, N, O) will be connected in a way that satisfies their bonding preferences and the octet rule.
3. Step 3: Draw single bonds between the atoms according to the chosen connectivity (H–C–N–O or H–C=N=O, etc.) and distribute the remaining valence electrons as lone pairs to satisfy the octet rule for each atom (except hydrogen, which only needs 2 electrons).
4. Step 4: Adjust the bonding by adding double or triple bonds where necessary to ensure that each atom (especially C, N, and O) has a complete octet and the total number of electrons matches the valence count from Step 1.
5. Step 5: Verify the formal charges on each atom to find the most stable Lewis structure. The best Lewis structure will have formal charges closest to zero and place negative charges on the more electronegative atoms (like oxygen).