Electron Configuration of Transition Metals

Here we're going to be talking about the electron configuration of the transition metals. And these are going to be a little trickier than some of the other electron configurations we've been doing because there's a few rules that we need to remember. Much of what was special about transition metals has to do with

half-filled and filled subshells. We've talked about three main types of subshells, S, P, and D, and it's kind of important to remember what's half-filled and whole-filled because these are uh particularly stable. So, for an S subshell, a half-filled would be one and whole-filled would be two. So, we're just putting in there, this really

doesn't come into play that often, but it's important to just consider it. For a P subshell, half-filled would be three and whole-filled would be six. So, remember a P subshell can hold onto six electrons. Kind of the important one is that a D subshell can hold 10 if wholly filled and half-filled is only five.

So, we're going to find there's a couple places where this pops up, the stability of half-filled and whole-filled subshells, and this is one of them. So, when you're doing electron configurations and you see that you're dealing with a transition metal, you have to remember that 3D4 and 3D9 are special. So, we'll look at those here in

just a second, and the reason why is 3D4 is one electron away from being half-filled, and 3D9 is one electron away from being wholly filled. And they want that stability of being either half or whole filled so much that they will actually steal an S electron. So, they'll steal one of the 4S electrons to

become 3D5 or in the uh the other case, 3D10. And what this is going to do is reduce the number of S electrons. So, just remember 3D4 and 3D9 are special because they're one electron away from being half-filled and whole-filled. And what's going to happen is an S electron is going to jump from the 4S subshell