Which of the following best describes the correct Lewis dot structure for the neutral compound CH2NH (methylenimine)?

• A. The nitrogen atom forms a double bond with the carbon atom, and all atoms have complete octets.
• B. The nitrogen atom forms a triple bond with the carbon atom, and the hydrogen atoms are bonded to nitrogen.
• C. The nitrogen atom forms a single bond with the carbon atom, and the carbon atom has an incomplete octet.
• D. The carbon atom forms double bonds with both hydrogen atoms, and nitrogen is left with a lone pair.

Answer: (A)

Verified step by step guidance

1. Step 1: Determine the total number of valence electrons in CH2NH. Carbon has 4 valence electrons, each hydrogen has 1, nitrogen has 5, so sum them up: \$4 + (2 \times 1) + 5 + 1 = 12$ valence electrons.
2. Step 2: Arrange the atoms with carbon as the central atom bonded to two hydrogens and nitrogen. Hydrogen atoms can only form single bonds, so connect each hydrogen to carbon with a single bond, and connect carbon to nitrogen with a bond.
3. Step 3: Distribute the remaining valence electrons to satisfy the octet rule for carbon and nitrogen. Remember that hydrogen only needs 2 electrons (a single bond). Adjust bonding between carbon and nitrogen to achieve full octets, considering single, double, or triple bonds.
4. Step 4: Evaluate the possible bonding scenarios: a single bond between C and N may leave carbon with an incomplete octet; a triple bond may leave nitrogen with no lone pairs; a double bond can allow both atoms to have complete octets and nitrogen to retain a lone pair.
5. Step 5: Confirm that the final Lewis structure has all atoms with complete octets (except hydrogen), and that the bonding matches the valence electron count and typical bonding patterns (e.g., nitrogen usually has one lone pair). This will help identify the correct description among the options.