I was reading this article from Wikipedia on resonance structures: http://en.wikipedia.org/wiki/Resonance_(chemistry) What I do not understand is, what is meant by potential energy in terms of chemistry? In physics, potential energy is defined by location in a force field. What is it that determines potential energy in a compound or molecule? Is it the position of electrons to other electrons, electrons to nuclei? How does having lower potential energy make a molecule more stable? Explain in layman's terms please.