Chemistry Chemical Bonding and Molecular Structure

Water has only two lone pair and XeF₄ has two lone pair electron in opposite plane of the central atom.

σ1s < 1s < 2s < 2s < (2px = 2py) < 2pz < (2px = π2py) < *2pz is the correct order of energy of MO for homo nuclear diatomic species N?

AlCl? , BeCl? and PCl? does not obey octet rule.
AlCl? and BeCl? both are electron-deficient species having six electrons in valence shell of central atom whereas PCl? has ten electrons in valence shell of phosphorous.
The structures are :

λ = c/ν
λ = (3 * 10? ) / (1368 * 10³) = 219.298 m ≈ 219.3 m

The valence bond theory explains the covalent bond formation for two half-filled orbitals. The bond strength depends on several factors, including the extent of overlap of the two atomic orbitals. The bond strength is directly proportional to the extent of overlap.

In simple words, the greater the amount of overlap between two orbitals, the stronger the covalent bond will be.

JEE asks many questions based on the comparison of bond strength for two different pairs of atomic orbitals forming a covalent bond. For example, why H–F bond stronger than the F–F bond?

Maximum lone pair - lone pair repulsions are there in XeF?

O? (15) will have configuration σ1s²σ1s²σ2s²σ2s²σ2p? ² (π2p? ²=π2p? ²) (π*2p? ¹). This ion is paramagnetic.

The concept of delocalization or resonance can be explained for quantum mechanical atomic models in which electrons are considered to be spread over the entire molecular orbital.

The fundamental assumption of the valence bond theory contradicts the delocalization. The valence bond theory assumes that a covalent bond forms from the overlap of atomic orbitals on adjacent atoms, and electron density is localized between two specific nuclei.

That is why VBT cannot explain energy stabilization due to the resonance property.

H? O has a tetrahedral geometry and a bent shape with a bond angle of 104.5°, which is smaller than 109.5°. This is because of the presence of two lone pairs in H? O.

ClF? and XeF? have two lone pairs of electrons on central atom.