Draw the Lewis structure for CO, including any valid resonance structures. Which of the following statements is TRUE?
The correct answer and explanation is :
To begin with the Lewis structure for carbon monoxide (CO), we must first determine the valence electrons for each atom:
- Carbon (C) is in group 14 of the periodic table and has 4 valence electrons.
- Oxygen (O) is in group 16 and has 6 valence electrons.
The total number of valence electrons is:
- 4 (from C) + 6 (from O) = 10 valence electrons.
Next, we draw the skeletal structure. Carbon is the central atom, and oxygen is bonded to it. The first bond between C and O is a single bond, which uses 2 electrons. This leaves us with 8 electrons to be placed.
- We place 2 electrons as lone pairs on both carbon and oxygen atoms.
- After placing the lone pairs, carbon will have only 6 electrons around it, so it needs more electrons to satisfy the octet rule.
- We form a second bond between C and O, utilizing 2 more electrons. Now, carbon has 8 electrons, and oxygen has 6 electrons around it.
At this stage, we still have 2 electrons left. Oxygen will use these to form a triple bond with carbon, making a total of 10 electrons used.
The Lewis structure of CO is:
:C≡O:This shows a triple bond between carbon and oxygen, with lone pairs on both atoms.
Resonance Structures:
In the case of CO, no true resonance structures exist. The structure we have represents the most stable configuration because it allows both atoms to achieve an octet of electrons. The triple bond between C and O is a very strong and stable bond, and the lone pairs on the atoms are placed in a way that satisfies the octet rule.
Correct Answer and Explanation:
The correct answer is that carbon monoxide has no valid resonance structures because the molecule is already in its most stable form, where both carbon and oxygen fulfill the octet rule, and no alternative bonding arrangements are favorable.
Explanation:
Carbon monoxide (CO) has a triple bond between carbon and oxygen, with each atom having a lone pair. This structure satisfies the octet rule for both atoms, as both carbon and oxygen end up with 8 electrons in their valence shells. Given this structure’s stability, no other bonding arrangements (such as double or single bonds) would improve the molecule’s stability, and therefore no resonance structures are needed. The molecule is best represented by this single, stable configuration.