Question

BeF2 molecule is linear while SF2 is angular explain

Answer 1

becuz BeF2 has no lone pair over it. where has two lone pairs are present on sulphur atom in SF2 which cause its distortion to bent shape

Answer 2

Answer: The shape of the molecule is known by its hybridization which is calculated by the formula:

$:{\text{Number of electrons}} =\frac{1}{2}[V+N-C+A]$

where, V = number of valence electrons present in central atom

N = number of monovalent atoms bonded to central atom

C = charge of cation

A = charge of anion

a) For $BeF_2$

${\text{Number of electrons}} =\frac{1}{2}[2+2-0+0]=2$

The number of electrons is 2 that means the hybridization will be $sp$ and the electronic geometry of the molecule will be linear. There are two atoms around the central carbon and hence the molecular geometry will also be linear.

b) For $SF_2$

${\text{Number of electrons}} =\frac{1}{2}[6+2-0+0]=4$

The number of electrons is 4 that means the hybridization will be $sp^3$. But as there are two atoms around the central atom, the third and fourth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be angular.