The decreasing valuse of bond angles from `NH_(3) (106^(@))` to `SbH_(3)(101^(@))` down group -15 of the periodic table is due to .

Options

A. decreasing lp-bp repulsion
B. decreasing electronegativity
C. increasing bp-bp repulsion
D. increasing p-orbital character in `sp^(3)`

Answer

B

Explanation

The bond angle decreases on moving down the group due to decrease in bond pair-bond pair repulsion.
`{:(NH_(3), PH_(3), AsH_(3), SbH_(3), BiH_(3)),(107^(@), 94^(@), 92^(@), 91^(@), 90^(@)):}`
NOTE : This can also be explained by the fact that as the size of central atom increases `sp^(3)` hybrid orbital becomes more distinct with increasing size of central atom i.e. pure p-orbitals are utilized in M-H bonding