Draw the lewis structure of CO2. how many lone pairs (non-bonding pairs) are present?
The Correct Answer and Explanation is:
Lewis Structure of CO(_2)
To draw the Lewis structure for carbon dioxide (CO(_2)), follow these steps:
- Count total valence electrons:
- Carbon (C) has 4 valence electrons.
- Oxygen (O) has 6 valence electrons each.
- Total valence electrons: ( 4 + 6 + 6 = 16 ).
- Arrange atoms:
- Carbon is the central atom because it is less electronegative than oxygen. Arrange oxygen atoms on either side of the carbon atom: O-C-O.
- Create single bonds:
- Connect carbon to each oxygen with a single bond. This uses (2 \times 2 = 4) electrons, leaving (16 – 4 = 12) electrons.
- Complete the octet rule for outer atoms (oxygen):
- Place three lone pairs (6 electrons) around each oxygen. This uses (6 \times 2 = 12) electrons, leaving (0) electrons.
- Check the octet rule for the central atom (carbon):
- Carbon currently has only 4 electrons (from the single bonds). To satisfy its octet, create double bonds by sharing two lone pairs from the oxygen atoms with the carbon atom. This results in:
:O::C::O:Each atom now has a full octet: carbon has 8 electrons from two double bonds, and each oxygen has 8 electrons (4 in bonds and 4 as lone pairs).
Lone Pairs in CO(_2)
- Each oxygen atom retains 4 non-bonding electrons (2 lone pairs).
- There are 2 oxygen atoms, so there are (2 \times 2 = 4) lone pairs in the molecule.
Explanation
CO(_2) is a linear molecule due to its central carbon atom being bonded to two oxygen atoms via double bonds. Each oxygen atom has two lone pairs to satisfy the octet rule. Lone pairs are critical for determining molecular geometry and polarity. In CO(_2), the symmetrical linear shape ensures it is nonpolar despite the polar C=O bonds, as dipole moments cancel each other.