Which of the following statements correctly describes the Lewis structure of the neutral compound CO (carbon monoxide)?

• A. CO has a triple bond between C and O, with one lone pair on C, two lone pairs on O, and a formal charge of -1 on C and +1 on O.
• B. CO has a single bond between C and O, with three lone pairs on O and two lone pairs on C, and no formal charges.
• C. CO has a triple bond between C and O, with no lone pairs on either atom, and no formal charges.
• D. CO has a double bond between C and O, with two lone pairs on each atom, and no formal charges.

Answer: (A)

Verified step by step guidance

1. Determine the total number of valence electrons available for the CO molecule by adding the valence electrons of carbon (4 electrons) and oxygen (6 electrons), giving a total of 10 valence electrons.
2. Draw a skeletal structure with carbon and oxygen connected by a bond. Since CO is a diatomic molecule, start with a single bond between C and O, which uses 2 electrons.
3. Distribute the remaining electrons to satisfy the octet rule for both atoms. Add lone pairs to oxygen and carbon as needed, and consider multiple bonds (double or triple) to achieve full octets.
4. Calculate the formal charges on carbon and oxygen for each possible Lewis structure using the formula: Formal charge = (Valence electrons) - (Nonbonding electrons) - (Bonding electrons / 2). This helps identify the most stable structure with the lowest formal charges.
5. Compare the structures and select the one where carbon and oxygen have formal charges of -1 and +1 respectively, a triple bond between them, one lone pair on carbon, and two lone pairs on oxygen, as this best represents the actual Lewis structure of CO.