How many bonding pair are present in carbon(iv)oxide?

Analysis

The question asks for the number of bonding pairs in a molecule of carbon(IV) oxide ($CO_2$). A bonding pair refers to a pair of electrons shared between two atoms to form a covalent bond.

Concept

Carbon(IV) oxide ($CO_2$) is a linear molecule. To determine the number of bonding pairs, we look at its Lewis structure:

1. Carbon (C) is in Group 4, meaning it has 4 valence electrons. It needs 4 more to complete its octet.
2. Oxygen (O) is in Group 6, meaning it has 6 valence electrons. Each oxygen atom needs 2 more to complete its octet.
3. To achieve stability, the carbon atom forms a double bond with each of the two oxygen atoms.

Solution

• Structure: $O = C = O$
• Bonding: • The bond between Carbon and the first Oxygen consists of 2 shared pairs of electrons (a double bond). • The bond between Carbon and the second Oxygen also consists of 2 shared pairs of electrons (a double bond).
• Calculation: • Number of bonding pairs = (Pairs in first double bond) + (Pairs in second double bond) • Number of bonding pairs = 2 + 2 = 4 bonding pairs.

Conclusion

In the $CO_2$ molecule, there are 4 shared pairs of electrons (bonding pairs) in total, distributed as two double bonds.

Exam Tip

When counting bonding pairs, remember that a single bond counts as 1 pair, a double bond counts as 2 pairs, and a triple bond counts as 3 pairs. Always draw the Lewis structure first to avoid missing any bonds!