The Lewis electron-dot structure of H2CO has how many nonbonding electron pairs, bonding electron pairs, and what is the carbon-oxygen bond order?

• A. 2 nonbonding pairs, 4 bonding pairs, bond order of 2
• B. 0 nonbonding pairs, 6 bonding pairs, bond order of 1
• C. 3 nonbonding pairs, 3 bonding pairs, bond order of 3
• D. 1 nonbonding pair, 5 bonding pairs, bond order of 1

Answer: (A)

Verified step by step guidance

1. Step 1: Identify the total number of valence electrons in H2CO. Hydrogen (H) has 1 valence electron, carbon (C) has 4, and oxygen (O) has 6. Calculate the total by adding these together: 2(1) + 4 + 6.
2. Step 2: Draw the skeletal structure of H2CO. Place carbon in the center, as it is the least electronegative element that can form multiple bonds. Attach the two hydrogen atoms to carbon and the oxygen atom to carbon.
3. Step 3: Distribute the total valence electrons around the atoms to satisfy the octet rule for carbon and oxygen, and the duet rule for hydrogen. Start by forming single bonds between C-H and C-O.
4. Step 4: Check if all atoms have a complete octet (or duet for hydrogen). If not, consider forming double bonds. In this case, form a double bond between carbon and oxygen to satisfy the octet rule for both atoms.
5. Step 5: Count the number of bonding pairs (shared electron pairs) and nonbonding pairs (lone pairs) on each atom. Determine the bond order of the carbon-oxygen bond by counting the number of bonds between them.