Answer to Question #98468 in General Chemistry for Soph

Question

How does adding a lone pair affect the position of existing atoms and lone pairs?

Answer 1

According to a so-called VSEPR theory, each lone electron pair repulses other covalent electron pairs, which affect deformation of the molecular geometry. Water molecule and ammonia molecule are the classical examples of this effect. The lone pair on the nitrogen atom in NH₃ molecule affects pyramidal geometry instead of trigonal planar, which would be more favorable without the lone pair.