Question

Does $N{O_2}^ -$ have a dipole?

Answer 1

The molecule can be said to have a dipole when it has a dipole moment. It is given by the product of charge and the separated distance. $N{O_2}^ -$ exists in the geometry of bent, in which the two nitrogen-oxygen bonds are not exactly opposite, which leads to the polarity of the molecule.

Complete answer:
Nitrogen and oxygen combine with other forms of different types of molecules like nitrosonium ion, nitrogen dioxide, nitrite ion. The nitrite ion has the molecular formula of $N{O_2}^ -$ , which consists of one nitrogen atom, two oxygen atoms and one negative charge on the oxygen atom.
Nitrogen is an element with atomic number $7$ and the valence electrons on nitrogen atom will be $5$
Oxygen is an element with atomic number $8$ and the valence electrons on oxygen atom will be $6$ , as two oxygen atoms were there in nitrite ion, the total valence electrons on oxygen atom will be $12$
One negative charge indicates one electron.
Thus, the total valence electrons in nitrite ion will be $5 + 2\left( 6 \right) + 1 = 18$
These $18$ electrons six electrons exist as bonding electrons, and remaining twelve electrons exist as lone pairs of electrons on nitrogen, and two oxygen atoms.
Nitrite ions exist in bent shape, in which the bonds are not exactly opposite. Thus, the molecule has a dipole moment.
Thus, $N{O_2}^ -$ has a dipole.

Note:
Out of the total electrons that are involved in the nitrite ion exist as lone pair of electrons, and bond pair of electrons. Due to the lone pair of electrons, the geometry of the molecule is bent. The molecules like water also have a dipole moment which exists in bent shape.