Name: Hybridisation in SF₆ Molecule
Uploaded: 2019-07-19
Duration: 2 min 31 s
Description: Understand the bonding present in the case of sulphur hexafluoride. This video illustrates that the hybridisation present in the case of sulphur hexafluoride...

Question

Given energy sequence for molecular orbitals. Explain paramagnetic behaviour and bond order in oxygen molecule. Compare the bonding and anti bonding orbitals?

Accepted Answer

To give energy sequence for molecular orbitals:
For lighter molecules (having electrons less than $14$ ) is $σ (1 s) < σ * (1 s) < σ (2 s) < σ * (2 s) < π (2 p_{x}) = π (2 p_{y}) < σ (2 p_{z}) < π * (2 p_{x}) = π * (2 p_{y}) < σ * (2 p_{z})$

Electronic configuration of $O$ -atom ( $Z = 8$ ) is $1 s^{2} 2 s^{2} 2 {p_{x}}^{2} 2 {p_{y}}^{1} 2 {p_{z}}^{1}$ . Total number of electrons in $O_{2}$ molecule is $16, 8$ from each oxygen atom. Therefore, the electronic configuration of oxygen molecule will be $[σ (1 s)]^{2} [σ * (1 s)]^{2} [σ (2 s)]^{2} [σ * (2 s)]^{2} [σ (2 p_{z})]^{2} [π (2 p_{x})]^{2} = [π (2 p_{y})]^{2} [π * (2 p_{x})]^{1} [[π * (2 p_{y})]^{1}$ $N_{b} = 10, N_{a} = 6 B . O . = \frac{1}{2} (N_{b} - N_{a}) = \frac{1}{2} (10 - 6) = 2$

The presence of two unpaired electrons in the $π * (2 p_{x}) and π * (2 p_{y})$ molecular orbitals accounts for its paramagnetic nature.

To compare bonding and anti bonding orbitals.

Bonding orbitals Anti bonding orbitals

They are formed when the lobes of the combining atomic orbitals have same sign. They are formed when the lobes of the combining atomic orbitals have opposite sign.

Bonding orbitals Anti bonding orbitals

It possesses lower energy. It possesses higher energy.

Bonding orbitals Anti bonding orbitals

The bonding molecular orbital is stabilized relative to the energy of isolated atoms. The Anti bonding molecular orbital is stabilized relative to the energy of isolated atoms.

Given energy sequence for molecular orbitals. Explain paramagnetic behaviour and bond order in oxygen molecule. Compare the bonding and anti bonding orbitals?

Important Questions on Chemical Bonding and Molecular Structure

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