Question

How many of the species are paramagnetic?

$N_{2}O,NO,N{O}_2,O_2,N{O}_2^{+},N{O}^{+},C{O}^{+}$

• A. 2
• B. 3
• C. 5
• D. 4

Answer 1

Answer: (D)

Number of valance electrons in $N_{2}O=5+6+5=16$

All electrons can be paired up and there is no free electron. $N_{2}O$ molecule is therefore diamagnetic.

Number of valance electrons in $NO=5+6=11$

All electrons can not be paired up and there is an odd electron responsible for magnetism. $NO$ molecule is therefore paramagnetic.

Number of valance electrons in $N{O}_2=5+6+6=17$

All electrons can not be paired up and there is an odd electron responsible for magnetism. $N{O}_2$ molecule is therefore paramagnetic.

Number of valance electrons in $O_2=6+6=12$

All electrons can be paired up and there is no free electron. $O_2$ molecule is exception and is paramagnetic.

Number of valance electrons in $N{O}_2^{+}=5+6+6-1=16$

All electrons can be paired up and there is no free electron. $N{O}_2^{+}$ molecule is therefore diamagnetic.

Number of valance electrons in $N{O}^{+}=5+6-1=10$

All electrons can be paired up and there is no free electron. $N{O}^{+}$ molecule is therefore diamagnetic.

Number of valance electrons in $C{O}^{+}=4+6-1=9$

All electrons can not be paired up and there is an odd electron. $C{O}^{+}$ molecule is therefore paramagnetic.

Overall 4 species are paramagnetic including $NO,N{O}_2,O_2$ and $C{O}^{+}$