Which species has a bond order of 2.5 and is paramagnetic?
For NO : (sigma 1s)² (sigma^* 1s)² (sigma 2s)² (sigma^* 2s)² (sigma 2pz)² (pi 2px)² (pi 2py)² (pi^* 2px)¹ . Bonding = 10, antibonding = 5. Bond order = (10 - 5/2) = 2.5 , with 1 unpaired electron (paramagnetic).
Ref: NCERT Class 11 Chemistry > Chapter 4: Chemical Bonding and Molecular Structure > Topic: Molecular Orbital Theory - MOT and Bond Order and Magnetic Properties