Resonance Structures and Isomers

[RahilVaknalliDis3A]

What is the difference between a resonance structure and an isomer?

[nickjadidian 1A]

Good question! The main thing to keep in mind is that isomers have different chemical properties, while different resonance structures have the same essential properties (in other words, they are different versions of the same molecule). The temptation to confuse resonance with isomers may arise from the fact ISOTOPES of different elements exist in nature, which are different "versions" of the same element, and contribute to the overall weighted averages of atomic weight as seen in the periodic table. Don't confuse isotopes and isomers. Resonances are similare to isotopes because the different structures are possible, and can contribute in varying amounts to the overall shape of molecules by affecting the bond length. The key here is that certain structures are more stable than others, and therefore contribute more to the experimentally observed bond lengths. Even though resonance has some shared likeness with elemental isotopes, this isn't to say they are isomers. For a better discussion of isomers, refer to this source:

https://socratic.org/questions/how-do-resonances-and-isomers-differ

[JamesAntonios 1E]

A resonance structure means that the molecule is the same but the bonds can be interchanged. The bonds blur together in (dotted line). In isomers, this is referring to only organic compounds. The bonds do not blur with one another. Resonance structures can refer to both organic and inorganic molecules. Resonance structures differ only in electron and bond position. Isomers, on the other hand, differ in both electron and atom position. This can cause changes in the overall molecular identity.