Chemical Bonding and Molecular Structure Test - 7

In the absence of a lone pair, sp³d hybridisation gives trigonal bipyramidal geometry.
The shape of the molecule can be predicted according to the VESPER theory.
Three of the five hybridised orbitals lie in the equatorial plane with a 120° angle between them.
Two bonds lie in the axial plane and the molecule has a trigonal bipyramidal geometry.

PF₅ : sp³d hybridisation

If the four hybrid orbitals include a d-orbital (dsp² hybridization), the square planar geometry is thermodynamically favourable for the molecules.
Square planar geometry corresponds to dsp² hybridisation.
Tetrahedral geometry corresponds to sp³ hybridisation.
Trigonal bipyramidal geometry corresponds to sp³d hybridisation.
Octahedral geometry corresponds to sp³d² hybridisation.

This option is correct because the electronic configuration of Be = 1s² 2s².
Therefore, the electronic configuration of Be^- = 1s² 2s² 2p¹.
So, the stable electronic configuration of Be has broken up and it is highly unstable.

In case of carbon tetrachloride, each carbon forms four covalent bonds with four chlorine atoms. Each carbon has four electrons in the valence shell and each chlorine has seven electrons in the valence shell. Carbon shares its four electrons and each chlorine shares one electron. By doing so, the octets of both become complete.

In PCl₅, P has 5 electrons in its valence shell. It shares 5 electrons with Cl atom. Thus, Cl atom contains 8 electrons in its valence shell, but P has 10 electrons in its valence shell and thus, has expanded octet. Hence, in PCl₅, octet rule is not valid.

Based on Fajans' rule (Covalent nature × Charge on metal), the correct order of covalent nature is LiCl < BeCl₂ < BCl₃ < CCl₄.

Aluminum and fluorine have a large difference in their electronegativity values. So, they will combine to form ionic bonds.