Why are resonance structures used when drawing the nitrate ion, NO_3^-?

• A. Because resonance structures indicate the presence of ionic bonds in the nitrate ion.
• B. Because the nitrate ion alternates rapidly between three distinct structures.
• C. Because resonance structures show the movement of atoms within the ion.
• D. Because the actual structure is a hybrid of multiple possible Lewis structures, reflecting delocalized electrons.

Answer: (D)

Verified step by step guidance

1. Understand that resonance structures are multiple Lewis structures that differ only in the placement of electrons, not atoms.
2. Recognize that in the nitrate ion (NO_3^-), the double bond can be placed between the nitrogen and any one of the three oxygen atoms, creating three possible Lewis structures.
3. Know that none of these individual Lewis structures alone accurately represents the true electronic structure of the nitrate ion.
4. Learn that the actual structure is a resonance hybrid, meaning the true electron distribution is a blend of all resonance forms, leading to delocalized electrons over the oxygen atoms.
5. Conclude that resonance structures are used to depict this delocalization and to show that the bonding in nitrate ion is not fixed to one single arrangement but is a hybrid of multiple contributing structures.