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Electron configuration for f block element Nd

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Lecturer: Let's do a warm up where we figure out the electron configuration of Xenon right over here and then we can use that as the basis for starting to explore the electron configurations of F block elements. And in particular, we'll try to figure out the electron configuration of Neodymium. I always have trouble pronouncing these. Neodymium I believe is how it's pronounced. So let's first work on Xenon. I encourage you to actually pause the video and try to come up with the electron configuration for Xenon on your own. So I'm assuming you've had a go at it so we can just go through it. So it's going to be one S two then we go to the second period. Two S two and then we're going to the two P subshell. So one, two, three, four, five, six. Two P six then three s two then three p six then we go four s two and now we are in the D block. And remember, the D block, even though we're in the fourth period, we're going to actually fill in the three D subshell. We take the period minus one, so it's going to be three D, and to fill it up we have one, two, three, four, five, six, seven, eight, nine, 10, three D 10. Then you're back in the P block and since you're in the fourth period, it's gonna be four P, and once again to fill it up, you have six electrons. And then we go to the fifth period. Five S two and then we're going to go... The period is five but we're in the D block so we're going to go back to the four D subshell. Four D 10 and then we come back and Xenon perfectly fills out the five P subshell. Five P six. So that's the electron configuration of Xenon. So now let's think about what the electron configuration of Neodymium is. So one thing that you're saying, "Hey, "what's going on with this F block right over here? "Just kind of this island of elements." And it's really not an island. The reason that they put these colors here is because the F block actually belongs right here and if people had more width on pages to display these periodic tables, they would shove the D and the P blocks over to the right and stuff the F blocks right over here. And we actually did that and I actually like to look at it that way because it makes it clear it's not really an island and it actually kind of fits in the pattern of the periodic table. That is right over here. This right over here is our F block. So that is our... This right over here is our f block. So given that, lets figure out the electron configuration for Neodymium. And I'll give you a hint. In the D block you go back and back fill one subshell below the one shell below the period that you're in. In the F block you go two, you go back two shells. So here, we're not filling out the six F subshell, not even the five F subshell, but the four F subshell. So given that, figure out how much more do we have to add. How much more do we have to go past Xenon in order to get its electron configuration. So I encourage you to pause the video and figure that out right now for Neodymium. So I'm assuming you've had a go at it. So Neodymium is going to have the electron configuration of Xenon so Xenon gets us right over. It's the highest atomic number noble gas that has a smaller atomic number than Neodymium. So we can start with that, which we already saw is fairly involved. And then to that we just add the incremental higher energy electrons. So now we're in the sixth period so we're gonna go six S two, that's that right over there. That's six S two and now we're filling, we're gonna start going into the F subshell but it's not gonna be the sixth shell, it's gonna go two. It's gonna be our period minus two so it's gonna be four. Let me use a color you can see. So this gonna be, we are four electrons into that subshell. One, two, three, four so it's gonna be four F four. So we're in the sixth period but since we're in the F block, we're gonna go back, fill it to the fourth shell. That's the fourth shell right over there. And we are one, two, three, four, four electrons into it. And so this is neat shorthand because the other way to write the electron configuration of Neodymium would have been to do this. Would have been to write down all of this, let me do that. To have all of this, let me copy and paste it. Actually I think that's going to take up too much space, let's see. So. To write all of that, copy and paste. To write all of that and then to add to that the six S two. Six S two and the four F four. Four F four and so hopefully you appreciate that this is a slightly more efficient way to write it.