Which of the following is a nonpolar molecule?

A. A nitrogen monoxide molecule [tex]\(\text{(NO)}\)[/tex]

B. A nitrogen molecule [tex]\(\left( \text{N}_2 \right)\)[/tex]

C. A bent nitrogen dioxide molecule [tex]\(\left( \text{NO}_2 \right)\)[/tex] with nitrogen in the center

D. A linear nitrogen oxide molecule [tex]\(\left( \text{N}_2\text{O} \right)\)[/tex] with nitrogen in the center



Answer :

To determine which of the given molecules is nonpolar, we need to analyze each molecule's structure and the distribution of electrons within each molecule.

A. Nitrogen monoxide (NO):
- Nitrogen monoxide consists of one nitrogen atom and one oxygen atom.
- Nitrogen and oxygen have different electronegativities, with oxygen being more electronegative.
- This difference in electronegativity results in a polar covalent bond.
- Therefore, NO is a polar molecule.

B. Nitrogen molecule ([tex]$N_2$[/tex]):
- A nitrogen molecule consists of two nitrogen atoms.
- Both nitrogen atoms have the same electronegativity.
- The electrons are shared equally between the two nitrogen atoms, resulting in no dipole moment.
- Therefore, [tex]$N_2$[/tex] is a nonpolar molecule.

C. Bent nitrogen dioxide (NO_2):
- Nitrogen dioxide consists of one nitrogen atom and two oxygen atoms arranged in a bent shape.
- Nitrogen and oxygen have different electronegativities, with oxygen being more electronegative.
- The bent structure leads to an uneven distribution of charge.
- Therefore, NO_2 is a polar molecule.

D. Linear nitrogen oxide ([tex]$N_2O$[/tex]):
- Dinitrogen monoxide consists of two nitrogen atoms and one oxygen atom, with the arrangement being N-N-O.
- The central nitrogen atom has differing electronegativities with the nitrogen and oxygen atoms it's bonded to.
- This leads to an uneven distribution of electrons.
- Therefore, [tex]$N_2O$[/tex] is a polar molecule.

After analyzing all the molecules, the nonpolar molecule among the choices is:

B. A nitrogen molecule ([tex]$N_2$[/tex])