Key Idea N does not have d -orbitals but other group 15 elements have d -orbitals. All the given compounds i.e., BiF5,PF5,AsF5 and SbF5 exist. Only nitrogen is not able to form pentahalides because the second shell contains a maximum of eight electrons i.e., four bonds. The subsequent elements have suitable d -orbitals and form s -pentahalides.