In the previous video, we used Vesper to figure out the shape and internal bonding of carbon dioxide. Now we want to look at a new molecule. H2CO. H2CO is formaldehyde, or more properly called methanol. Formaldehyde has two valence electrons in the hydrogen, four for the carbon, and six from the oxygen. So we have 12 electrons to play with. Now in this case, carbon is going to be the central atom, because hydrogen can't be. So if I put carbon in the middle, and I can put a hydrogen on either side, and then I put an oxygen up here, well if I create three bonds, that just used six electrons. So I have six left. I can't put any on the hydrogen, so they have to go on the oxygen. But the problem is if I do that, I've used up all my electrons, and carbon is not stable. So the only way to stabilize that is to take two electrons away from one of the oxygen and create a double bond. And that is your Lewis structure for formaldehyde methanol. But now that doesn't determine the shape of the molecule. In order to figure out the shape, we have to look at Vesper. We have to look at the three sites on the central atom. This single bond here, this single bond here, and this double bond here, and see how they will repel each other. So if I'm back at FET, the formaldehyde molecule has two single bonds, those are your two hydrogens, and then a double bond where the oxygen is. And you can see that things settle out to this nice 120 degree angle, which makes sense if you're trying to maximize the distance between three sites. We call this a trigonal planar shape, it's a flat triangle. And that's true for both the molecular geometry and the electron geometry. Three sites get as far away from each other by making 120 degree internal bond angle. So formaldehyde H2CO, with its three sites on the central atom, the double bond and the two single bonds, creates a trigonal planar shape with internal bond angles of 120 degrees. So, we have a trigonal planar shape, which is a flat triangle. So, we have a trigonal planar shape, which is a flat triangle. And we have a trigonal planar shape, which is a flat triangle. And we have a trigonal planar shape, which is a flat triangle. And we have a trigonal planar shape, which is a flat triangle.