Drawing the Resonance Structures for O3

Transcript: We can draw O3 different ways. First, we can draw it with a double bond on the left and a single bond on the right. And this works: we're using all 18 valence electrons for O3, and each of the atoms has a full outer shell. It has eight valence electrons. But we could also draw it with the double bond on the other side so that it's basically a mirror image. They're the same structures in the sense that they have three Oxygens, have 18 valence electrons and the octets are satisfied in each structure. We call these resonance structures.

So you might ask, why draw resonance structures for ozone? Here's the thing: in nature, the actual ozone molecule, the O3 molecule, is not either one of these. It's an average of them. But as we draw Lewis structures and we follow those rules, it's a little bit hard to think that way. So we end up drawing resonance structures for ozone. We could also draw it a little bit differently to show that average. So here, instead of a double and a single, we have two 1.5 bonds. So you can see that dotted line means half a bond. So this is kind of showing you that average between the two resonance structures.

But again, when we draw those resonance structures, it's to kind of get around a limitation with how we have these rules to draw Lewis structures. This is really what the molecule would look like in the real world. This is Dr. B. with the resonance structure for O3, ozone. Thanks for watching.