 OK, so let me find one of these questions. How many nodal planes are contained in each of the following orbitals? OK, well, let's just do one orbital at a time, OK? So because I think there's enough material that we could talk about that doesn't really have to only do with just nodal points, OK? So let's do, well, let's do the one from the quiz, the 4py orbital, OK? So let's draw it first, the x, y, and z axes, so z axes like that. We said it was the y, right? So p, so s orbital, remember, is like a sphere, OK? And remember, this is a two-dimensional, you know, surface, so I can't really show a sphere very well, OK? And a p, is it like a dumbbell? If you think that kind of looks like a dumbbell or whatever. And then the d, right now we'll just say the clover leaf. We'll just stop with there for right now. And I know there's like that dz squared that's that weird looking one, like a dumbbell with a ring around it, and some other things. But let's just, for right now, the d. And we said we were looking for the 4p y. So we said this is s, the clover leaf shape, I don't know. So the y is going to be on the y one. It is an energy hardcore. And so it asked also how many nodal planes are contained. Well, the way to find the number of nodes is so you know the energy level of this. Everybody hopefully could tell me the energy level of this is 4. So the number of nodes is going to be the energy level minus 1. So the number of nodes equals 3 because 4 minus 1 equals 3. OK, also we know something else. We know L, an angular momentum, a quantum number. So in this case, if it's a p orbital, it's 1, right? So that tells you the number of angular nodes. So the number of angular nodes. There must be some other kind of nodes, too. They're called radial nodes. A radial node is going to be the total number of nodes minus the number of angular nodes. Makes sense, hopefully. So we've got three nodes total, minus 1 angular node. So there's two radial nodes. Is that OK? So I'll blow this up a little bit. It's the same as L. L is the quantum number, the second quantum number. So every p is 1 at L, right? L is 0 for S, 1 for D, 2 for D, 3 for F. You know that, right? Yeah. So let's draw a picture and show the nodes. So in this case, I guess we could have done it on this other picture. What we call the angular node is the one on the plane there. So it's on that zx point. So do you see that? So going through it like that. So it goes through that point. A node means zero electron density, a place of zero electron density. The other two nodes are angular nodes. So when we draw those, we need to draw a picture like this. And what we'll do is find those within. So that's one of the angular nodes, and the other one is just inside of them. So there's three nodes. One, did I say angular or main radial? So one angular, two radial. So there is the plane and the radials are within the actual orbit. So we'll do a couple more of these and see if you get them. Are there any questions on this one?