Resonance Structures

[kristinalaudis3e]

How do I know the true length of bonds when there are resonance structures? Specifically, how do I know which ones contribute the most?

[Benjamin_Hugh_3F]

The true bond length will be the average of all resonance structures since they act as the same molecule's contributing structures. To determine which resonance structure contributes the most, you need to compare the formal charge. The structure with the least number of formal charges will be more stable; thus, more preferred.

[Margaret Wang 2D]

You can't know the specific length of bonds in a resonance structure, just that it is between two numbers. As stated above, assign formal charges to every atom of every resonance structure and the ones with the most formal charges closer to 0 contributes the most.

[Marcus Lagman 2A]

Hello.

As everyone is saying, the formal charge is definitely the solution in which resonance structure is the most stable. As for the bond length, it's an average between all Lewis structures since the electrons are delocalized, causing overall lower energy. This is what stabilizes the structure, making it apparent that molecules do not shift between Lewis structures but remains in one as an average.

I hope this helps!

[Sabrina Galvan 3J]

The resonance structures that will contribute the most are the ones with the smallest magnitudes of charges, with the negative charge being on the most electronegative atom. This makes the most stable resonance structure.