Question

Arrange the species O2+, O2, O2-, O2^(2-) in order of increasing O-O bond length?

Thanks!

Answer 1

Concepts and reason

The concept of molecular orbital theory is used to solve such type of problems. According to molecular orbital theory, two atomic orbital combine with each other and formed two or more molecular orbitals.

First, calculate the valance electrons of all the given species and then write the molecular electronic configuration of each species and after that calculate the bond order of the given species.

Fundamentals

Bond order:

Bond order is the number of chemical bonds between two atoms.

To determine the bond order of any molecule by using following formula.

……(1)

Bond length:

If the bond between two atoms is covalent then the distance between these atoms is known as bond length.

The relation between bond order and the bond length is:

As per above relation, higher the bond order, shorter is the bond length and lesser the bond order, longer is the bond length.

The electronic configuration of O₂⁺ is given as shown below:

Substitute the value of electrons in bonding orbitals and in antibonding orbitals in equation (1)

Now,

=

=

The electronic configuration of O₂^- is:

Substitute the value of electrons in bonding orbitals and in antibonding orbitals in equation (1)

Now,

Bond order =

=

=

The electronic configuration of is shown below.

Now,

Bond order =

=

= 2

The electronic configuration of O₂^2- is:

Now,

Bond order =

=

=

The bond order of the given species is:

The increasing order O-O bond length is shown below:

Ans:

The increasing order O-O bond length is shown below: