NO2- is the nitrite ion. It has three atoms: one nitrogen N and two oxygen O atoms. To identify the possible resonance structures, we need to consider the arrangement of electrons and bonds in the molecule.1. First resonance structure:In this structure, the nitrogen atom is double bonded to one of the oxygen atoms and single bonded to the other oxygen atom. The double-bonded oxygen atom has two lone pairs of electrons, while the single-bonded oxygen atom has three lone pairs of electrons. This gives the single-bonded oxygen atom a formal charge of -1, while the nitrogen and double-bonded oxygen atoms have a formal charge of 0.2. Second resonance structure:This structure is similar to the first one, but the positions of the double and single bonds are switched. Now, the nitrogen atom is double bonded to the other oxygen atom and single bonded to the first oxygen atom. The double-bonded oxygen atom has two lone pairs of electrons, while the single-bonded oxygen atom has three lone pairs of electrons. This gives the single-bonded oxygen atom a formal charge of -1, while the nitrogen and double-bonded oxygen atoms have a formal charge of 0.These two resonance structures contribute to the overall stability of the nitrite ion by delocalizing the negative charge over the two oxygen atoms. The actual structure of the nitrite ion is a hybrid of these two resonance structures, with the nitrogen atom having a partial double bond to both oxygen atoms. This delocalization of electrons and charge helps to stabilize the molecule, making it less reactive than if the charge were localized on a single atom.