 Okay guys, so we just built this electron configuration for an atom that we took off the periodic table. Which one is this electron configuration for? Aluminum. Aluminum, right? And how do I know that? It's because, you know, I count the number of electrons here or I can look at the 3P and say there's one electron in it so I can look up there and see that aluminum has that electron configuration, right? So this is aluminum. So if I wanted to, I could ask myself, well, where are the inner electrons located and where are the valence electrons located? So if I wanted to draw a line in between where the inner electrons are located and the valence electrons, remember the valence electrons are in their own valence shell, okay? So a shell is designated by that number that we talked about, the principal energy level, okay? So if I wanted to discuss where the valence ones were, where would I put the line? Between the 3S and the 2P. Yeah, so between the 3S and the 2P, right? Because the 3s, that's the next energy level up, the valence energy level. Does that make sense? So let's just draw a line there. So these are the valence electrons and these down here, what do we call them? Yeah, the inner electron. So remember, we called anything that has the same energy level. We just called it something. Do you guys remember what we called it? A shell. Yeah. So this boxed groups of electrons, these 2S and 2P, or the four orbitals there, that inclusively is called a shell of electrons, okay? So this is an electron shell. So there are portions of that shell, as you guys well know. So there's the 2S and the 2P portions, okay? So if we wanted to box those off, that would be a sub-shell. So we already learned this, so I want you to help me out. So I just boxed one of these things that is able to carry 2 electrons. What would I call that thing? An orbital, right? That's an orbital. And what's that thing that's inside of an orbital? Yeah, that's an electron. So you guys should be able to distinguish these different portions of the electron diagram. Questions on this stuff? Okay, good.