Question

Which of the following is paramagnetic ?
A. `NO^(-)`
B. `O_(2)^(2-)`
C. `CN^(-)`
D. `CO`

Answer 1

Correct Answer - A
Number of electrons in `NO^(-)=7+8+1=16`
`:.` MOEC of `NO^(-) sigma 1s^(2), overset(**) sigma 1s^(2) sigma 2s^(2), overset(**) sigma 2s^(2), sigma 2p_(z)^(2)`
`pi 2 P_(x)^(2) ~~ pi p_(y)^(2), overset(**) pi p_(x)^(1)~~ overset(**) pi2pi_(y)^(1)`
Hence, paramagnetic due to the presece of unparied electron in `overset(**), and overset(**) 2p_(y)` orbitals.