Sigma molecular orbitals are not symmetrical around the bonding axis.a)Trueb)FalseCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Sigma molecular orbitals have center of symmetry, so they have symmetrical around the bonding axis.

Answer

According to the nomenclature, sigma molecular orbitals are symmetrical around the bonding axis and the pi molecular orbitals are not symmetrical around the bonding axis. So the given statement is false.

Answer

Sigma Molecular Orbitals are not symmetrical around the bonding axis:

Sigma (σ) molecular orbitals are formed by the head-to-head overlap of atomic orbitals along the bonding axis. These orbitals are commonly found in sigma bonds, which are characterized by a direct overlap of orbitals.

Symmetry in Molecular Orbitals:

In molecular orbital theory, the symmetry of molecular orbitals plays a crucial role in determining the properties and behavior of molecules. Symmetry can be described by the mathematical concept of group theory, which helps to classify and analyze molecular orbitals based on their symmetry properties.

Symmetry of Sigma Molecular Orbitals:

Sigma molecular orbitals are formed by the end-to-end overlap of atomic orbitals along the bonding axis. The bonding and antibonding sigma molecular orbitals have different symmetries.

1. Bonding Sigma Molecular Orbital (σ_b)
- This orbital is formed by the in-phase overlap of atomic orbitals.
- It is symmetrical around the bonding axis.
- The electron density is concentrated between the nuclei of the bonding atoms.
- This orbital contributes to the stability of the molecule and the formation of a sigma bond.

2. Antibonding Sigma Molecular Orbital (σ_ab)
- This orbital is formed by the out-of-phase overlap of atomic orbitals.
- It is not symmetrical around the bonding axis.
- The electron density is concentrated away from the region between the nuclei of the bonding atoms.
- This orbital does not contribute to the stability of the molecule and weakens the sigma bond.

Conclusion:

The statement 'Sigma molecular orbitals are not symmetrical around the bonding axis' is false. The bonding sigma molecular orbital (σ_b) is indeed symmetrical around the bonding axis. However, the antibonding sigma molecular orbital (σ_ab) is not symmetrical around the bonding axis. The shape and symmetry of molecular orbitals are important in understanding the bonding and properties of molecules.

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