Are bf3 and nf3 symmetrical or unsymmetrical molecules? explain.

is symmetrical and is unsymmetrical.

Explanation: Formula used  for calculating hybridization:

1.

where, V = number of valence electrons present in central atom i.e. boron= 3

N = number of monovalent atoms bonded to central atom=3

C = charge of cation = 0

A = charge of anion = 0

The number of electrons is 3 that means the hybridization will be and the electronic geometry of the molecule will be trigonal planar as there are three atoms around the central atom, the molecule will be symmetrical.

2.

where, V = number of valence electrons present in central atom i.e. nitrogen= 5

N = number of monovalent atoms bonded to central atom=3

C = charge of cation = 0

A = charge of anion = 0

The number of electrons is 4 that means the hybridization will be and the electronic geometry of the molecule will be tetrahedral.

But as there are three atoms around the central atom the 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 trigonal pyramidal and hence will be unsymmetrical.