Question

The species having octahedral shape is:
(A) $S{F_6}$
(B) $B{F_4}^ -$
(C) $PC{l_5}$
(D) $B{O_3}^{3 - }$

Answer 1

Hybridization: Mixing of atomic orbitals which results in the formation of new hybrid orbitals during the chemical bond formation, are known as hybridization. Hybridization occurs when electrons of s and p orbitals react to each other, then hybridization takes place to balance the energy levels.

Complete step by step solution:
First of all let us talk about hybridization and why it happens.
Hybridization: Mixing of atomic orbitals which results in the formation of new hybrid orbitals during the chemical bond formation, are known as hybridization. Hybridization occurs when electrons of s and p orbitals react to each other during the chemical bond formation, then hybridization takes place to balance the energy levels. We know that there is a difference between the energies of s and p-orbitals. s-orbitals have less energies in comparison with p-orbitals. To balance this energy difference hybridization takes place. After the hybridization the energies of all the orbits formed are the same. For example: in $s{p^3}$ hybridization one s and three p-orbitals takes place in the hybridization. Hence after hybridization four hybrid orbitals are formed which have the same energies.
Here we are having compounds
i) $S{F_6}$ in this molecule the central atom i.e. sulphur has total six electrons in its valence shell and in the molecule we have six fluorine atoms so it shares one electron with each fluorine atom. So this molecule has six bond pairs and no lone pair. So its structure is octahedral.
ii) $B{F_4}^ -$ in this molecule the central atom i.e. boron has three electrons in its valence shell and in this molecule there is one negative charge on the boron atom so the central atom will have four electrons and four fluorine are there in the molecule. So boron will share one electron with each fluorine atom. Hence its shape will be tetrahedral.
iii) $PC{l_5}$ in this molecule the central atom i.e. phosphorus has five electrons in its valence shell and five chlorine atoms are there in the molecule. So phosphorus will share one electron with each chlorine atom. Hence its shape will be trigonal bipyramidal.
iv) $B{O_3}^{3 - }$ in this molecule the central atom i.e. boron three electrons in its valence shell and in this molecule there is three negative charge on the molecule and three oxygen are there in the molecule each carry one negative charge. So boron will share one electron with each oxygen atom. Hence its shape will be a triangular shape.

So, option A is the correct answer.

Note:
Number of hybrid orbitals formed after the hybridization is equal to the total number of orbitals taking part in the hybridization. For example if hybridization is $s{p^2}$ hybridized then one s and two p- orbitals take part in the hybridization and total three hybrid orbitals will be formed after the hybridization.