Which of the following is a valid resonance form for nitrite, NO₂ 1 - , that obeys the octet rule for each atom in the formula and uses the appropriate number of valence electrons?

Question

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Resonance structures occur when different structures can be drawn for a molecule or ion that differ only in the placement of electrons. The actual structure is then considered to be an average of all of the resonance structures.

In the case of nitrite, NO₂ 1 -, there are three possible resonance structures that can be drawn.

I) This structure has a double bond between the nitrogen and one of the oxygen atoms, and a single bond between the nitrogen and the other oxygen atom. This satisfies the octet rule for each atom, and uses the appropriate number of valence electrons.

II) This structure has a double bond between the nitrogen and the other oxygen atom, and a single bond between the nitrogen and the first oxygen atom. While this structure still satisfies the octet rule for each atom, it does not use the appropriate number of valence electrons. Each oxygen should have 6 valence electrons in the structure, but this structure only gives them 4 each. Therefore, this structure is not valid.

III) This structure has a single bond between the nitrogen and both oxygen atoms. This also satisfies the octet rule for each atom and uses the appropriate number of valence electrons.

Because structures I and III are both valid resonance structures, the answer is D) I and III only.

Which of the Following Is a Valid Resonance Form for Nitrite