The pronounced change from non-metallic to metallic behaviour and also increase in the basic nature of oxides from nitrogen to bismuth in group 15 is principally due to increasing size of the atom. The ionisation potential of nitrogen is very high on account of it small size. however, ionisation potential decreases regularly on desceding the group.
Which one of the following is a strongest base?

Options

A. `AsH_(3)`
B. `SbH_(3)`
C. `PH_(3)`
D. `NH_(3)`

Answer

D

Explanation

`NH_(3)` to `BiH_(3)` : Thermal stability decreases `N_(2)O_(3)` to `Bi_(2)O_(3)` : Acidic nature of oxides decrease
`NF_(5)` : does not exists due to lack of empty d-orbitals in the valence shell of nitrogen
`NH_(3)` to `BiH_(3)` : Lewis basic nature decreases