Final answer:
NO₂ contains two equivalent N-O bonds due to resonance, which represents an average of multiple bonding structures, rather than distinct single and double bonds or lone pairs of electrons.
Step-by-step explanation:
The molecule NO₂ (nitrogen dioxide) exhibits a bonding structure that can be explained through the concept of resonance. Resonance is the idea that the actual electronic structure of a molecule is an average of all valid Lewis structures, known as resonance forms. The molecule of NO₂, which has an odd number of valence electrons, cannot be perfectly described with a single Lewis structure. Instead, different arrangements suggest the presence of double bonds and single bonds with a lone electron. However, experiments confirm that both N-O bonds in NO₂ are identical in length and strength, highlighting that the real structure is a resonance hybrid, similar to how a rhinoceros is neither solely a dragon nor a unicorn but has characteristics of both.
Thus, NO₂ does not have lone pairs on nitrogen, but instead has two equivalent bonds that are the result of resonance. The valency of nitrogen in NO₂ is fulfilled by the sharing of these electrons through resonance structures, making it appear as though there are two double bonds in the molecule.