Final answer:
In determining the relative stability of resonance structures, factors that contribute to stability include small or no formal charges, and negative formal charges being on more electronegative atoms. Scenario II regarding separation of charges does not increase stability. Thus, the correct answer is (C) I and III only.
Step-by-step explanation:
One of the main uses of calculating formal charges is to determine the relative stability of resonance structures. When assessing the stability of resonance structures, several factors can contribute to increased stability:
- Having small or no formal charges, as opposed to larger formal charges, will make a resonance structure more stable.
- Ensuring negative formal charges are placed on more electronegative atoms, as opposed to less electronegative atoms, typically results in a more stable structure.
In reference to the scenarios provided, scenario I is correct because structures with charges closest to zero are more stable. Scenario III is also correct because corresponding negative formal charges with more electronegative atoms increases stability. Scenario II, however, is incorrect as having more separation between opposite charges does not inherently increase stability and in fact, structures are generally more stable when opposite charges are closer together to allow for charge cancellation. Therefore, the correct answer to the question is (C) I and III only.