The pronounced change from non-metallic behaviour and also increase in the basicity of oxides from nitrogen to bismuth in group `15` is principally due to incresing size of the atoms. The ionisation potential of nitrogen is very high on account of its small size. However, ionisation potential decreases regularly on descending the group.
Which one of the following fluorides does not exist ?

Options

A. `NF_(5)`
B. `PF_(5)`
C. `AsF_(5)`
D. `SbF_(5)`

Answer

B

Explanation

` NF _ 5 ` does exist because N does not fom pentahalides due to the absence of d - orbital in its valence shell. While P, As and Sb from pentahalides of the general formula ` MX _ 5 ` ( where, M = P, As and Sb ) due to the presence of vacant d - orbitals in their respective valence shell.