Draw the Lewis dot structure for carbon dioxide (CO2) and identify all bonding and non-bonding electron pairs
The Correct Answer and Explanation is:
Here’s the Lewis dot structure for carbon dioxide (CO2), along with an explanation of its bonding and non-bonding electron pairs.
In CO2, the central atom is carbon, which forms two double bonds with two oxygen atoms. Each oxygen atom has two lone pairs of electrons. Carbon has no lone pairs in this molecule.
Bonding electron pairs:
- Each C=O double bond consists of two shared pairs of electrons (four electrons total per bond)
- There are two double bonds, so there are 4 bonding pairs in total
Non-bonding (lone) electron pairs:
- Each oxygen atom has two lone pairs
- Total lone pairs = 2 oxygen atoms × 2 lone pairs = 4 lone pairs
Explanation
Carbon dioxide (CO2) is a linear molecule composed of one carbon atom and two oxygen atoms. To draw its Lewis structure, we begin by counting the total number of valence electrons. Carbon has 4 valence electrons, and each oxygen has 6, giving a total of 4 + (2 × 6) = 16 valence electrons.
Carbon is the central atom because it can form more bonds than oxygen. We place the two oxygen atoms on either side of the carbon atom. Initially, we form single bonds between carbon and each oxygen, using 4 electrons. This leaves 12 electrons to distribute.
Next, we place lone pairs on the oxygen atoms to satisfy their octets. Each oxygen needs 6 more electrons (3 lone pairs), using up all 12 remaining electrons. However, this leaves carbon with only 4 electrons (2 bonds), which is not enough to satisfy its octet.
To resolve this, we convert lone pairs from each oxygen into bonding pairs, forming double bonds. Each oxygen donates one lone pair to form a second bond with carbon. Now, carbon has 8 electrons (4 bonds), and each oxygen has 8 electrons (2 bonds + 2 lone pairs), satisfying the octet rule for all atoms.
The final structure shows carbon with two double bonds and no lone pairs, and each oxygen with two lone pairs. The molecule is linear due to the arrangement of electron domains around the central carbon atom.
