Question

explain the VSEPRT with an example

Answer 1

according to VESPR theory
a) in polyatomic molecules the least electrinegative atom is called central atom . with which all others atoms are linked .
b) the geometry of the molecule depend upon the total number of valence electron pairs (either bond or lone pairs) around the central atom and the repulsions between these electron pairs.
c) the repulsion among pairs increases as bp-bp <lp-bp <lp-lp presence of lone pairs of electrons greatly affect the bond angle .
some example .
the bond angle of PF3> PCl3. the PF3 molecule has lone pairs of electrons on F atom and p has vacant d-orbitals. the small size of F atom leads to p pi-d pi bonding in PF3 . the double bond formation increases bomd pair bond pair repulsion ,so the bond angle of PF3 is greater then PCl3.

d) pi bond don't affect the stereochemistry of a molecule .however multiple bond orbital , repel others more strongly then singly bond orbital, increasing bond angle .we discuss this concept example above.

e)a lone pairs and double bond repulsion is much greater then a lone pairs electron and double bond repulsion.i.e.
N=O=N bond angle is greater then
O=N--> O-