shapes and repulsion forces

i am little bit confused with shapes of molecules
let me explain
for example trigonal planar has 3 bonded pair and has angle 120 between bonds because electrons in bond repel from each other
if it has 1 lone pair and two bonded pair repulsion increases pair of electrons move as far as possible and it has angle 118.5 so IF THEY MOVE FURTHER A PART WHY ANGLE DECREASES?????

Reply 1

RoyalSheepy

20

Original post by Qer

i am little bit confused with shapes of molecules
let me explain
for example trigonal planar has 3 bonded pair and has angle 120 between bonds because electrons in bond repel from each other
if it has 1 lone pair and two bonded pair repulsion increases pair of electrons move as far as possible and it has angle 118.5 so IF THEY MOVE FURTHER A PART WHY ANGLE DECREASES?????

Because the bond angles decrease, as lone pair repulsion is greater than bond repulsion. So therefore the lone pairs exert a force on the bond pairs, forcing the bonds to become closer; hence the bond angles decreasing.

(edited 6 years ago)

Reply 2

Qer

OP

16

Original post by royalsheepy

because the bond angles decrease, as lone pair repulsion is greater than bond repulsion. So therefore the lone pairs exert a force on the bond pairs, forcing the bonds to become closer; hence the bond angles decreasing.