Question

What is the orbital hybridization in $ BrC{{l}_{3}} $ ?

Answer 1

Hint :We know that for solving this question first we need to understand the concepts of hybridization. Hybridization which is also known as orbital hybridization is the concept of mixing atomic orbitals with new hybrid orbitals.

Complete Step By Step Answer:
The concept of hybridization is based on the difference in energies, shapes, and sizes when compared with the component of atomic orbitals. Thus, this concept is suitable for the pairing of electrons to form chemical bonds according to the valence bond theory.
The different types of hybridization are; $ \text{s}{{\text{p}}^{\text{3}}}\text{,s}{{\text{p}}^{\text{2}}}\text{,sp,ds}{{\text{p}}^{\text{2}}}\text{,s}{{\text{p}}^{\text{3}}}\text{d,s}{{\text{p}}^{\text{3}}}{{\text{d}}^{\text{2}}}\text{,s}{{\text{p}}^{\text{3}}}{{\text{d}}^{\text{3}}}\text{ } $
Start by drawing the Lewis structure of the compound. The total number of valence electrons will be $ 28,~7~ $ from each of the three chlorine atoms and $ 7 $ from the bromine atom. Out of the $ 28~ $ valence electrons $ 24 $ will be used to complete the octets of the chlorine atoms - each chlorine atom has $ 3 $ lone pairs and shares a single bond with bromine.
As you can see, the remaining $ 4 $ valence electrons are placed on bromine as lone pairs. This means that bromine will have a total of $ 10 $ valence electrons, which is possible because it can have an expanded octet.
 $ :\underset{\scriptscriptstyle\centerdot\centerdot}{\ddot{C}}l-\underset{\scriptscriptstyle\centerdot\centerdot}{\ddot{B}}r(:\underset{\scriptscriptstyle\centerdot\centerdot}{\ddot{C}}l)-\underset{\scriptscriptstyle\centerdot\centerdot}{\ddot{C}}l: $
The hybridization of the bromine atom is determined by counting the regions of electron density that surround the atom that represents the steric number. So, bromine has $ 2 $ lone pairs, and $ 3 $ single bonds, which means it has a steric number of $ 5. $
The steric number will also tell you how many hybrid orbitals an atom has. In this case, five hybrid orbitals would correspond to an $ s{{p}^{3}}d $ hybridized atom. Because of the two lone pairs of electrons, the molecular geometry of the bromine trichloride molecule will be T-shaped, not trigonal bipyramidal.

Note :
When we refer to hybridization Bent rule is an important concept. Bent rule is defined and explained as the relationship between the orbital hybridization of central atoms in the molecules and the electronegativity of substituent.