Which of the following is the correct Lewis dot structure for carbon monoxide (CO)?

• A. C triple bond O, with one lone pair on C and two lone pairs on O
• B. C double bond O, with two lone pairs on C and two lone pairs on O
• C. C triple bond O, with two lone pairs on C and one lone pair on O
• D. C single bond O, with three lone pairs on C and three lone pairs on O

Answer: (A)

Verified step by step guidance

1. Step 1: Determine the total number of valence electrons available for bonding in CO. Carbon has 4 valence electrons and oxygen has 6 valence electrons, so total valence electrons = 4 + 6 = 10.
2. Step 2: Connect the carbon and oxygen atoms with a bond. Start with a single bond, which uses 2 electrons, leaving 8 electrons to be distributed as lone pairs or additional bonds.
3. Step 3: Use the remaining electrons to satisfy the octet rule for both atoms. Add lone pairs and multiple bonds as needed to ensure both carbon and oxygen have 8 electrons around them.
4. Step 4: Consider the possibility of multiple bonds (double or triple bonds) between carbon and oxygen to achieve full octets and minimize formal charges. Calculate formal charges for each structure to find the most stable arrangement.
5. Step 5: Identify the Lewis structure with a triple bond between carbon and oxygen, one lone pair on carbon, and two lone pairs on oxygen, as this arrangement satisfies the octet rule and results in the lowest formal charges on both atoms.