Question

According to the VSEPR model, the progressive decrease in the bond angles in the series of molecules CH₄, NH₃, and H₂O is best accounted for by the _________.

Answer 1

lone pair-bond pair repulsion is best accounted for decrease in bond angle

Step-by-step explanation:

Bond angle in each compounds depends on presence of lone pair on central atom.

In
`CH_(4)`, there is no lone pair on C atom. So, no lone pair-bond pair repulsion is present here. Hence
`\angle H-C-H` is
`109^(0)5^(')`

In
`NH_(3)`, there is one lone pair on N atom. So, one lone pair-bond pair repulsion is present here. Hence
`\angle H-N-H` is
`107^(0)`

In
`H_(2)O`, there are two lone pairs on O atom. So, two lone pair-bond pair repulsion are present here. Hence
`\angle H-O-H` is
`104^(0)5^(')`

So, lone pair-bond pair repulsion is best accounted for decrease in bond angle