Solved Examples Bond Order Formula
Example 1: Calculate the bond order of the O2 molecule.
Solution:
The electronic configuration of an O2 molecule according to the Molecular Orbital Theory is as follows:
(σ1s)2(σ∗1s)2(σ2s)2(σ∗2s)2(σ1pz)2(π2px)2 = (π2py)2(π∗2px)1 = (π∗2py)1
From the above electronic configuration,
Nb = 10, Na = 6
Thus,
= 1/2 (10 -6) = 2
So, the bond order of the O2 molecule is 2 which means that a double bond exists between the two O atoms.
Example 2: Calculate the bond order of the N2 molecule.
Solution:
The electronic configuration of the N2 molecule according to the Molecular Orbital Theory is as follows:
(σ1s)2(σ∗1s)2(σ2s)2(σ∗2s)2(σ1pz)2(π2px)2 = (π2py)2
From the above electronic configuration,
Nb = 10, Na = 4
Thus,
= 1/2 (10 -4) = 3
So, the bond order of the N2 molecule is 3 which means that a triple bond exists between the two N atoms.
Example 3: Arrange the following in increasing order of their bond length: O22-, O2, O2–, O2+
Solution:
Bond order of the given molecules is as follows:
O22-= 1
O2 = 2
O2–= 2.5
O2+ = 1.5As we know the higher the bond order, the lower the bond length. Thus the increasing order of the given molecules is as follows:
O22- < O2+ < O2 <O2–
Bond Order Formula
Chemistry deals with various particles, atoms, or elements and the chemical reactions between them. All the chemical reactions that take place are directly the result of the formation or breaking of bonds between the elements. Whenever two atoms combine to form a molecule, they form bonds between themselves. These bonds may be ionic or covalent. In both cases, the electrons are the ones that play an important role in bond formation as any bond is the result of the transfer or sharing of electrons between two atoms. Thus the number of electrons involved in the formation of a molecule decides the number of bonds between the atoms. This leads to the definition of the term Bond Order. The term bond order was first coined by Linus Pauling and he is known to introduce the concept of bond order. Bond order is a very crucial and significant term in molecular orbital theory (MOT). In this article, we shall learn what is bond order and how to calculate it.