Question

The Diamagnetic Species is?
(A)$NO$
(B)$N{O_2}$
(C)${O_2}$
(D)$C{O_2}$

Answer 1

Hint: A species is said to be diamagnetic when all the electrons present in are paired, and it is not attracted to a magnetic field. If a particle has unpaired electrons then they are paramagnetic.

Complete step by step answer:
To understand this question we should first know about magnetism and its types,
Magnetism can be defined as attractive or repulsive forces produced by moving electric charge , there are usually 5 types – diamagnetism , para magnetism , ferromagnetism , antiferromagnetism and ferrimagnetism .diamagnetic materials are the materials that are repelled by a magnetic field and does not contain any unpaired electrons but ferromagnetic and paramagnetic are usually attracted by a magnetic field , and paramagnetic contains unpaired electrons. Some of the examples of diamagnetic substances are copper, zinc, water, superconductors are also considered as perfect diamagnetic materials because of their ability to eject electrons in all directions.
Here considering our question , we should check the diamagnetism in the options, as we know diamagnetic materials are devoid of unpaired electron , therefore the molecules having odd number of b valence electrons cannot be diamagnetic in nature,
Taking cases of $NO$ and $N{O_2}$ , option A and B
 $NO$ will have $5 + 6 = 11$ electrons
$N{O_2}$ will be having $5 + 2 \times 6 = 17$electrons
So this both can’t be diamagnetic
Then in option C, ${O_2}$ molecule will have $2 \times 6 = 12$ electrons, when we check its molecular orbital diagram, it has unpaired electron in antibonding MO, so this will also become paramagnetic in nature
Going for option D, $C{O_2}$ molecule has 10 valence electron, In its MO diagram also it have completely filled bonding orbitals, which make it diamagnetic in nature
Therefore the correct answer will be option D.

Note:
All materials display diamagnetism, but to a diamagnetic molecule the diamagnetism should be the only contribution to its magnetic behavior
Two strongest diamagnetic materials are graphite and bismuth, the forces created by a diamagnetism are weak force compared to paramagnetism and ferromagnetism