(Nb-Na)÷2 ,,,,where Nb is no. of electrons in bonding M.O. and Na is no. of electrons in antibonding M.O.

Bond Order of ClO2

Bond order is a measure of the stability of a chemical bond within a molecule. It indicates the number of chemical bonds between a pair of atoms. In the case of ClO2 (chlorine dioxide), we can determine its bond order by analyzing its Lewis structure and molecular orbital diagram.

1. Lewis Structure of ClO2:
The Lewis structure of ClO2 can be determined by following these steps:
- Count the total number of valence electrons: chlorine (Cl) contributes 7 valence electrons, and each oxygen (O) contributes 6 valence electrons. Therefore, the total is 7 + 2(6) = 19 valence electrons.
- Determine the central atom: Since chlorine is less electronegative than oxygen, it will be the central atom in ClO2.
- Connect the atoms with single bonds: Place the chlorine atom in the center and connect it with the two oxygen atoms using single bonds.
- Distribute the remaining electrons: Place the remaining electrons around the oxygen atoms first, and then distribute the remaining electrons around the chlorine atom. Ensure that each atom satisfies the octet rule (except for hydrogen, which follows the duet rule).

The Lewis structure of ClO2 is as follows:

O
//
Cl - O

2. Molecular Orbital Diagram:
To determine the bond order, we need to construct the molecular orbital diagram of ClO2. This diagram shows the distribution of electrons in the molecular orbitals formed by the overlapping of atomic orbitals.

- Start by writing the electron configurations of each atom: Chlorine has the electron configuration 1s2 2s2 2p6 3s2 3p5, and oxygen has the electron configuration 1s2 2s2 2p4.
- Determine the total number of valence electrons: In the case of ClO2, there are 19 valence electrons.
- Build the molecular orbital diagram: Combine the atomic orbitals of chlorine and oxygen to form molecular orbitals. Fill the molecular orbitals with the valence electrons, following the Aufbau principle and Pauli exclusion principle.

The molecular orbital diagram of ClO2 reveals the following:

- There are three molecular orbitals: σ, π1, and π2.
- The σ molecular orbital is lower in energy and is filled with 2 electrons.
- The π1 and π2 molecular orbitals are higher in energy and are filled with 4 electrons in total.

3. Calculation of Bond Order:
The bond order can be calculated using the formula:

Bond Order = (Number of bonding electrons - Number of antibonding electrons) / 2

- Count the number of bonding electrons: In ClO2, there are 6 bonding electrons (2 in the σ orbital and 4 in the π orbitals).
- Count the number of antibonding electrons: In ClO2, there are 2 antibonding electrons in the π orbitals.

Using the formula, the bond order of ClO2 is calculated as:

Bond Order = (6 - 2) / 2 = 4 / 2 = 2

Hence, the bond order of ClO2 is 2.

Conclusion:
In conclusion, the bond order of ClO2 is 2. This indicates that there are two chemical bonds between the chlorine and oxygen atoms in the molecule. The Lewis structure and molecular