[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:05.46,Default,,0000,0000,0000,,Let's figure out the electron configuration for nickel,
Dialogue: 0,0:00:05.47,0:00:06.94,Default,,0000,0000,0000,,right there.
Dialogue: 0,0:00:06.95,0:00:08.72,Default,,0000,0000,0000,,28 electrons.
Dialogue: 0,0:00:08.74,0:00:10.47,Default,,0000,0000,0000,,We just have to figure out what shells
Dialogue: 0,0:00:10.49,0:00:11.59,Default,,0000,0000,0000,,and orbitals they go in.
Dialogue: 0,0:00:11.61,0:00:12.76,Default,,0000,0000,0000,,28 electrons.
Dialogue: 0,0:00:12.78,0:00:14.29,Default,,0000,0000,0000,,So the way we've learned to do it is,
Dialogue: 0,0:00:14.30,0:00:16.18,Default,,0000,0000,0000,,we defined this as the s-block.
Dialogue: 0,0:00:16.20,0:00:18.89,Default,,0000,0000,0000,,And we can just remember that helium actually belongs here
Dialogue: 0,0:00:18.91,0:00:22.22,Default,,0000,0000,0000,,when we talk about orbitals in the s-block.
Dialogue: 0,0:00:22.24,0:00:23.92,Default,,0000,0000,0000,,This is the d-block.
Dialogue: 0,0:00:23.94,0:00:27.36,Default,,0000,0000,0000,,This is the p-block.
Dialogue: 0,0:00:27.38,0:00:29.46,Default,,0000,0000,0000,,And so we could start with the lowest energy electrons.
Dialogue: 0,0:00:29.47,0:00:31.61,Default,,0000,0000,0000,,We could either work forward or work backwards.
Dialogue: 0,0:00:31.64,0:00:33.58,Default,,0000,0000,0000,,If we work forwards, first we fill up
Dialogue: 0,0:00:33.60,0:00:36.57,Default,,0000,0000,0000,,the first two electrons going to 1s2.
Dialogue: 0,0:00:36.59,0:00:39.91,Default,,0000,0000,0000,,So remember we're doing nickel.
Dialogue: 0,0:00:39.93,0:00:44.42,Default,,0000,0000,0000,,So we fill up 1s2 first with two electrons.
Dialogue: 0,0:00:44.43,0:00:48.53,Default,,0000,0000,0000,,Then we go to 2s2.
Dialogue: 0,0:00:48.55,0:00:51.55,Default,,0000,0000,0000,,And remember this little small superscript 2 just means
Dialogue: 0,0:00:51.56,0:00:53.78,Default,,0000,0000,0000,,we're putting two electrons into that subshell
Dialogue: 0,0:00:53.80,0:00:55.53,Default,,0000,0000,0000,,or into that orbital.
Dialogue: 0,0:00:55.55,0:01:00.73,Default,,0000,0000,0000,,Actually, let me do each shell in a different color.
Dialogue: 0,0:01:00.75,0:01:02.74,Default,,0000,0000,0000,,So 2s2.
Dialogue: 0,0:01:02.76,0:01:06.17,Default,,0000,0000,0000,,Then we fill out 2p6.
Dialogue: 0,0:01:06.19,0:01:09.03,Default,,0000,0000,0000,,We fill out all of these, right there.
Dialogue: 0,0:01:09.05,0:01:11.47,Default,,0000,0000,0000,,So 2p6.
Dialogue: 0,0:01:11.49,0:01:14.62,Default,,0000,0000,0000,,Let's see, so far we've filled out 10 electrons.
Dialogue: 0,0:01:14.64,0:01:16.70,Default,,0000,0000,0000,,We've configured 10. You can do it that way.
Dialogue: 0,0:01:16.71,0:01:20.87,Default,,0000,0000,0000,,Now we're on the third shell. The third shell.
Dialogue: 0,0:01:20.88,0:01:22.24,Default,,0000,0000,0000,,So now we go to 3s2.
Dialogue: 0,0:01:22.26,0:01:23.36,Default,,0000,0000,0000,,Remember, we're dealing with nickel,
Dialogue: 0,0:01:23.50,0:01:27.34,Default,,0000,0000,0000,,so we go to 3s2.
Dialogue: 0,0:01:27.36,0:01:30.93,Default,,0000,0000,0000,,Then we fill out in the third shell the p orbital.
Dialogue: 0,0:01:30.95,0:01:35.19,Default,,0000,0000,0000,,So 3p6.
Dialogue: 0,0:01:35.21,0:01:38.52,Default,,0000,0000,0000,,We're in the third period, so that's 3p6, right there.
Dialogue: 0,0:01:38.54,0:01:40.52,Default,,0000,0000,0000,,There's six of them.
Dialogue: 0,0:01:40.54,0:01:44.62,Default,,0000,0000,0000,,And then we go to the fourth shell.
Dialogue: 0,0:01:44.64,0:01:46.09,Default,,0000,0000,0000,,I'll do it in yellow.
Dialogue: 0,0:01:46.11,0:01:51.41,Default,,0000,0000,0000,,So we do 4s2. 4s2.
Dialogue: 0,0:01:51.43,0:01:53.25,Default,,0000,0000,0000,,And now we're in the d-block.
Dialogue: 0,0:01:53.27,0:01:55.92,Default,,0000,0000,0000,,And so we're filling in one, two, three, four,
Dialogue: 0,0:01:55.95,0:01:58.73,Default,,0000,0000,0000,,five, six, seven, eight in this d-block.
Dialogue: 0,0:01:58.75,0:02:00.58,Default,,0000,0000,0000,,So it's going to say d8.
Dialogue: 0,0:02:00.60,0:02:03.00,Default,,0000,0000,0000,,And remember, it's not going to be 4d8.
Dialogue: 0,0:02:03.01,0:02:05.83,Default,,0000,0000,0000,,We're going to go and backfill the third shell.
Dialogue: 0,0:02:05.85,0:02:07.99,Default,,0000,0000,0000,,So it will be 3d8.
Dialogue: 0,0:02:08.01,0:02:11.96,Default,,0000,0000,0000,,So we could write 3d8 here.
Dialogue: 0,0:02:11.98,0:02:14.16,Default,,0000,0000,0000,,So this is the order in which we fill,
Dialogue: 0,0:02:14.17,0:02:18.31,Default,,0000,0000,0000,,from lowest energy state electrons to highest energy state.
Dialogue: 0,0:02:18.33,0:02:20.84,Default,,0000,0000,0000,,But notice the highest energy state electrons,
Dialogue: 0,0:02:20.86,0:02:22.85,Default,,0000,0000,0000,,which are these that we filled in, in the end,
Dialogue: 0,0:02:22.87,0:02:25.90,Default,,0000,0000,0000,,these eight, these went into the third shell.
Dialogue: 0,0:02:25.92,0:02:27.12,Default,,0000,0000,0000,,So when you're filling the d-block,
Dialogue: 0,0:02:27.14,0:02:29.71,Default,,0000,0000,0000,,you take the period that you're in minus one.
Dialogue: 0,0:02:29.73,0:02:32.16,Default,,0000,0000,0000,,So we were in the fourth period in the periodic table,
Dialogue: 0,0:02:32.18,0:02:33.69,Default,,0000,0000,0000,,but we subtracted one, right?
Dialogue: 0,0:02:33.71,0:02:38.52,Default,,0000,0000,0000,,This is 4 minus 1.
Dialogue: 0,0:02:38.54,0:02:42.91,Default,,0000,0000,0000,,So this is the electron configuration for nickel.
Dialogue: 0,0:02:42.93,0:02:44.71,Default,,0000,0000,0000,,And of course if we remember,
Dialogue: 0,0:02:44.73,0:02:46.65,Default,,0000,0000,0000,,if we care about the valence electrons,
Dialogue: 0,0:02:46.67,0:02:50.39,Default,,0000,0000,0000,,which electrons are in the outermost shell,
Dialogue: 0,0:02:50.41,0:02:53.44,Default,,0000,0000,0000,,then you would look at these right here.
Dialogue: 0,0:02:53.46,0:02:55.39,Default,,0000,0000,0000,,These are the electrons that will react,
Dialogue: 0,0:02:55.41,0:02:57.72,Default,,0000,0000,0000,,although these are in a higher energy state.
Dialogue: 0,0:02:57.74,0:02:59.59,Default,,0000,0000,0000,,And these react because they're the furthest.
Dialogue: 0,0:02:59.61,0:03:01.68,Default,,0000,0000,0000,,Or at least, the way I visualize them is that
Dialogue: 0,0:03:01.70,0:03:04.42,Default,,0000,0000,0000,,they have a higher probability of being further
Dialogue: 0,0:03:04.44,0:03:07.22,Default,,0000,0000,0000,,from the nucleus than these right here.
Dialogue: 0,0:03:07.24,0:03:08.84,Default,,0000,0000,0000,,Now, another way to figure out
Dialogue: 0,0:03:08.86,0:03:11.70,Default,,0000,0000,0000,,the electron configuration for nickel--
Dialogue: 0,0:03:11.71,0:03:14.73,Default,,0000,0000,0000,,and this is covered in some chemistry classes,
Dialogue: 0,0:03:14.75,0:03:15.98,Default,,0000,0000,0000,,although I like the way we just did it
Dialogue: 0,0:03:15.99,0:03:17.55,Default,,0000,0000,0000,,because you look at the periodic table
Dialogue: 0,0:03:17.57,0:03:19.22,Default,,0000,0000,0000,,and you gain a familiarity with it,
Dialogue: 0,0:03:19.24,0:03:20.66,Default,,0000,0000,0000,,which is important, because then
Dialogue: 0,0:03:20.67,0:03:22.23,Default,,0000,0000,0000,,you'll start having an intuition
Dialogue: 0,0:03:22.25,0:03:24.60,Default,,0000,0000,0000,,for how different elements react with each other
Dialogue: 0,0:03:24.62,0:03:28.00,Default,,0000,0000,0000,,-- is to just say, oK, nickel has 28 electrons,
Dialogue: 0,0:03:28.02,0:03:31.60,Default,,0000,0000,0000,,if it's neutral. It has 28 electrons,
Dialogue: 0,0:03:31.62,0:03:33.88,Default,,0000,0000,0000,,because that's the same number of protons, which is the atomic number.
Dialogue: 0,0:03:33.90,0:03:36.56,Default,,0000,0000,0000,,Remember, 28 just tells you how many protons there are.
Dialogue: 0,0:03:36.58,0:03:38.01,Default,,0000,0000,0000,,This is the number of protons.
Dialogue: 0,0:03:38.03,0:03:39.70,Default,,0000,0000,0000,,We're assuming it's neutral.
Dialogue: 0,0:03:39.72,0:03:41.32,Default,,0000,0000,0000,,So it has the same number of electrons.
Dialogue: 0,0:03:41.33,0:03:43.31,Default,,0000,0000,0000,,That's not always going to be the case.
Dialogue: 0,0:03:43.33,0:03:45.37,Default,,0000,0000,0000,,But when you do these electron configurations,
Dialogue: 0,0:03:45.38,0:03:46.89,Default,,0000,0000,0000,,that tends to be the case.
Dialogue: 0,0:03:46.91,0:03:53.96,Default,,0000,0000,0000,,So if we say nickel has 28, has an atomic number of 28,
Dialogue: 0,0:03:53.98,0:03:56.35,Default,,0000,0000,0000,,so it's electron configuration we can do it this way, too.
Dialogue: 0,0:03:56.37,0:03:58.36,Default,,0000,0000,0000,,We can write the energy shells.
Dialogue: 0,0:03:58.38,0:04:03.74,Default,,0000,0000,0000,,So one, two, three, four.
Dialogue: 0,0:04:03.76,0:04:08.71,Default,,0000,0000,0000,,And then on the top we write s, p, d.
Dialogue: 0,0:04:08.73,0:04:10.45,Default,,0000,0000,0000,,Well we're not going to get to f.
Dialogue: 0,0:04:10.46,0:04:13.20,Default,,0000,0000,0000,,But you could write f and g and h and keep going.
Dialogue: 0,0:04:13.22,0:04:15.64,Default,,0000,0000,0000,,What's going to happen is you're going to fill this one first,
Dialogue: 0,0:04:15.66,0:04:20.15,Default,,0000,0000,0000,,then you're going to fill this one, then that one,
Dialogue: 0,0:04:20.17,0:04:23.78,Default,,0000,0000,0000,,then this one, then this one.
Dialogue: 0,0:04:23.80,0:04:24.91,Default,,0000,0000,0000,,Let me actually draw it.
Dialogue: 0,0:04:24.93,0:04:27.89,Default,,0000,0000,0000,,So what you do is, these are the shells that exist, period.
Dialogue: 0,0:04:27.91,0:04:30.86,Default,,0000,0000,0000,,These are the shells that exist, in green.
Dialogue: 0,0:04:30.88,0:04:33.92,Default,,0000,0000,0000,,What I'm drawing now isn't the order that you fill them.
Dialogue: 0,0:04:33.94,0:04:38.82,Default,,0000,0000,0000,,This is just, they exist. So there is a 3d subshell.
Dialogue: 0,0:04:38.84,0:04:41.46,Default,,0000,0000,0000,,There's not a 3f subshell.
Dialogue: 0,0:04:41.48,0:04:43.17,Default,,0000,0000,0000,,There is a 4f subshell.
Dialogue: 0,0:04:43.19,0:04:44.46,Default,,0000,0000,0000,,Let me draw a line here,
Dialogue: 0,0:04:44.47,0:04:46.23,Default,,0000,0000,0000,,just so it becomes a little bit neater.
Dialogue: 0,0:04:46.25,0:04:51.89,Default,,0000,0000,0000,,And the way you fill them is you make these diagonals.
Dialogue: 0,0:04:51.91,0:04:54.19,Default,,0000,0000,0000,,So first you fill this s shell like that,
Dialogue: 0,0:04:54.21,0:04:55.79,Default,,0000,0000,0000,,then you fill this one like that.
Dialogue: 0,0:04:55.81,0:04:58.15,Default,,0000,0000,0000,,Then you do this diagonal down like that.
Dialogue: 0,0:04:58.16,0:05:00.53,Default,,0000,0000,0000,,Then you do this diagonal down like that.
Dialogue: 0,0:05:00.55,0:05:02.66,Default,,0000,0000,0000,,And then this diagonal down like that.
Dialogue: 0,0:05:02.68,0:05:06.63,Default,,0000,0000,0000,,And you just have to know that there's only two can fit in s,
Dialogue: 0,0:05:06.65,0:05:08.80,Default,,0000,0000,0000,,six in p, in this case, 10 in d.
Dialogue: 0,0:05:08.81,0:05:10.76,Default,,0000,0000,0000,,And we can worry about f in the future,
Dialogue: 0,0:05:10.79,0:05:13.92,Default,,0000,0000,0000,,but if you look at the f-block on a periodic table,
Dialogue: 0,0:05:13.94,0:05:15.69,Default,,0000,0000,0000,,you know how many there are in f.
Dialogue: 0,0:05:15.71,0:05:17.03,Default,,0000,0000,0000,,So you fill it like that.
Dialogue: 0,0:05:17.05,0:05:18.44,Default,,0000,0000,0000,,So first you just say, OK.
Dialogue: 0,0:05:18.45,0:05:20.96,Default,,0000,0000,0000,,For nickel, 28 electrons.
Dialogue: 0,0:05:20.98,0:05:22.96,Default,,0000,0000,0000,,So first I fill this one out.
Dialogue: 0,0:05:22.98,0:05:26.65,Default,,0000,0000,0000,,So that's 1s2. 1s2.
Dialogue: 0,0:05:26.67,0:05:32.00,Default,,0000,0000,0000,,Then I go, there's no 1p, so then I go to 2s2.
Dialogue: 0,0:05:32.02,0:05:35.23,Default,,0000,0000,0000,,Let me do this in a different color.
Dialogue: 0,0:05:35.25,0:05:37.62,Default,,0000,0000,0000,,So then I go right here, 2s2.
Dialogue: 0,0:05:37.64,0:05:40.09,Default,,0000,0000,0000,,That's that right there.
Dialogue: 0,0:05:40.11,0:05:42.41,Default,,0000,0000,0000,,Then I go up to this diagonal, and I come back down.
Dialogue: 0,0:05:42.43,0:05:46.04,Default,,0000,0000,0000,,And then there's 2p6.
Dialogue: 0,0:05:46.05,0:05:47.50,Default,,0000,0000,0000,,And you have to keep track of how many electrons
Dialogue: 0,0:05:47.51,0:05:48.57,Default,,0000,0000,0000,,you're dealing with, in this case.
Dialogue: 0,0:05:48.59,0:05:50.13,Default,,0000,0000,0000,,So we're up to 10 now.
Dialogue: 0,0:05:50.15,0:05:51.74,Default,,0000,0000,0000,,So we used that one up.
Dialogue: 0,0:05:51.75,0:05:53.83,Default,,0000,0000,0000,,Then the arrow tells us to go down here,
Dialogue: 0,0:05:53.85,0:05:57.97,Default,,0000,0000,0000,,so now we do the third energy shell.
Dialogue: 0,0:05:57.99,0:06:00.71,Default,,0000,0000,0000,,So 3s2.
Dialogue: 0,0:06:00.72,0:06:02.63,Default,,0000,0000,0000,,And then where do we go next?
Dialogue: 0,0:06:02.65,0:06:03.75,Default,,0000,0000,0000,,3s2.
Dialogue: 0,0:06:03.77,0:06:05.43,Default,,0000,0000,0000,,Then we follow the arrow.
Dialogue: 0,0:06:05.44,0:06:08.18,Default,,0000,0000,0000,,We start there, there's nothing there,
Dialogue: 0,0:06:08.20,0:06:09.25,Default,,0000,0000,0000,,there's something here.
Dialogue: 0,0:06:09.26,0:06:11.85,Default,,0000,0000,0000,,So we go to 3p6.
Dialogue: 0,0:06:11.87,0:06:15.88,Default,,0000,0000,0000,,And then the next thing we fill out is 4s2.
Dialogue: 0,0:06:15.90,0:06:19.36,Default,,0000,0000,0000,,So then we go to 4s2.
Dialogue: 0,0:06:19.38,0:06:21.14,Default,,0000,0000,0000,,And then what's the very next thing we fill out?
Dialogue: 0,0:06:21.16,0:06:22.56,Default,,0000,0000,0000,,We have to go back to the top.
Dialogue: 0,0:06:22.58,0:06:24.94,Default,,0000,0000,0000,,We come here and then we fill out 3d.
Dialogue: 0,0:06:24.96,0:06:27.20,Default,,0000,0000,0000,,And then how many electrons do we have left to fill out?
Dialogue: 0,0:06:27.22,0:06:32.93,Default,,0000,0000,0000,,So we're going to be in 3d. So 3d.
Dialogue: 0,0:06:32.95,0:06:34.76,Default,,0000,0000,0000,,And how many have we used so far?
Dialogue: 0,0:06:34.78,0:06:36.13,Default,,0000,0000,0000,,2 plus 2 is 4.
Dialogue: 0,0:06:36.15,0:06:37.33,Default,,0000,0000,0000,,4 plus 6 is 10.
Dialogue: 0,0:06:37.35,0:06:39.55,Default,,0000,0000,0000,,10 plus 2 is 12.
Dialogue: 0,0:06:39.57,0:06:40.71,Default,,0000,0000,0000,,18.
Dialogue: 0,0:06:40.73,0:06:41.81,Default,,0000,0000,0000,,20.
Dialogue: 0,0:06:41.83,0:06:44.40,Default,,0000,0000,0000,,We've used 20, so we have 8 more electrons to configure.
Dialogue: 0,0:06:44.41,0:06:50.28,Default,,0000,0000,0000,,And the 3d subshell can fit the 8 we need,
Dialogue: 0,0:06:50.29,0:06:51.76,Default,,0000,0000,0000,,so we have 3d8.
Dialogue: 0,0:06:51.78,0:06:54.14,Default,,0000,0000,0000,,And there you go, you've got the exact same answer that
Dialogue: 0,0:06:54.16,0:06:56.66,Default,,0000,0000,0000,,we had when we used the first method.
Dialogue: 0,0:06:56.68,0:06:58.23,Default,,0000,0000,0000,,Now I like the first method
Dialogue: 0,0:06:58.25,0:07:00.45,Default,,0000,0000,0000,,because you're looking at the periodic table the whole time,
Dialogue: 0,0:07:00.46,0:07:01.83,Default,,0000,0000,0000,,so you kind of understand an intuition
Dialogue: 0,0:07:01.85,0:07:03.24,Default,,0000,0000,0000,,of where all the elements are.
Dialogue: 0,0:07:03.26,0:07:06.80,Default,,0000,0000,0000,,And you also don't have to keep remembering,
Dialogue: 0,0:07:06.82,0:07:09.56,Default,,0000,0000,0000,,OK, how many have I used up as I filled the shells? Right?
Dialogue: 0,0:07:09.64,0:07:12.00,Default,,0000,0000,0000,,Here you have to say, i used two, then I used two more.
Dialogue: 0,0:07:12.02,0:07:13.77,Default,,0000,0000,0000,,And you have to draw this kind of elaborate diagram.
Dialogue: 0,0:07:13.79,0:07:15.63,Default,,0000,0000,0000,,Here you can just use the periodic table.
Dialogue: 0,0:07:15.64,0:07:18.36,Default,,0000,0000,0000,,And the important thing is you can work backwards.
Dialogue: 0,0:07:18.37,0:07:21.02,Default,,0000,0000,0000,,Here there's no way of just eyeballing this and saying,
Dialogue: 0,0:07:21.10,0:07:24.10,Default,,0000,0000,0000,,OK, our most energetic electrons are going to be
Dialogue: 0,0:07:24.16,0:07:24.86,Default,,0000,0000,0000,,3d8,
Dialogue: 0,0:07:24.88,0:07:29.21,Default,,0000,0000,0000,,and our highest energy shell is going to be 4s2.
Dialogue: 0,0:07:29.23,0:07:30.56,Default,,0000,0000,0000,,There's no way you could get that out of this
Dialogue: 0,0:07:30.58,0:07:34.59,Default,,0000,0000,0000,,without going through this fairly involved process.
Dialogue: 0,0:07:34.61,0:07:37.00,Default,,0000,0000,0000,,But when do you use this method, you can immediately say,
Dialogue: 0,0:07:37.01,0:07:44.71,Default,,0000,0000,0000,,OK, if I'm worried about element Zr, right here.
Dialogue: 0,0:07:44.73,0:07:46.70,Default,,0000,0000,0000,,If I'm worried about element Zr.
Dialogue: 0,0:07:46.72,0:07:49.28,Default,,0000,0000,0000,,I could go through the whole exercise of
Dialogue: 0,0:07:49.30,0:07:51.61,Default,,0000,0000,0000,,filling out the entire electron configuration.
Dialogue: 0,0:07:51.63,0:07:54.33,Default,,0000,0000,0000,,But usually the highest shell, or the highest energy electrons,
Dialogue: 0,0:07:54.35,0:07:55.73,Default,,0000,0000,0000,,are the ones that matter the most.
Dialogue: 0,0:07:55.74,0:07:56.98,Default,,0000,0000,0000,,So you immediately say, OK,
Dialogue: 0,0:07:57.03,0:08:00.19,Default,,0000,0000,0000,,I'm filling in 2 d there,
Dialogue: 0,0:08:00.21,0:08:03.53,Default,,0000,0000,0000,,but remember, d, you go one period below.
Dialogue: 0,0:08:03.55,0:08:05.28,Default,,0000,0000,0000,,So this is 4d2.
Dialogue: 0,0:08:05.29,0:08:06.76,Default,,0000,0000,0000,,Right? Because the period is five.
Dialogue: 0,0:08:06.78,0:08:10.59,Default,,0000,0000,0000,,So you say, 4d2. 4d2.
Dialogue: 0,0:08:10.60,0:08:16.01,Default,,0000,0000,0000,,And then, before that, you filled out the 5s2 electrons.
Dialogue: 0,0:08:16.02,0:08:19.60,Default,,0000,0000,0000,,The 5s2 electrons. And then you could keep going backwards.
Dialogue: 0,0:08:19.62,0:08:24.07,Default,,0000,0000,0000,,And you filled out the 4p6. 4p6.
Dialogue: 0,0:08:24.08,0:08:26.79,Default,,0000,0000,0000,,And then, before you filled out the 4p6.
Dialogue: 0,0:08:26.81,0:08:32.46,Default,,0000,0000,0000,,then you had 10 in the d here.
Dialogue: 0,0:08:32.48,0:08:33.67,Default,,0000,0000,0000,,But what is that?
Dialogue: 0,0:08:33.69,0:08:34.87,Default,,0000,0000,0000,,It's in the fourth period,
Dialogue: 0,0:08:34.89,0:08:37.54,Default,,0000,0000,0000,,but d you subtract one from it, so this is 3d10.
Dialogue: 0,0:08:37.56,0:08:39.44,Default,,0000,0000,0000,,So 3d10.
Dialogue: 0,0:08:39.45,0:08:41.97,Default,,0000,0000,0000,,And then you had 4s2.
Dialogue: 0,0:08:41.98,0:08:44.18,Default,,0000,0000,0000,,This is getting messy. Let me just write that.
Dialogue: 0,0:08:44.20,0:08:47.19,Default,,0000,0000,0000,,So you have 4d2.
Dialogue: 0,0:08:47.21,0:08:48.46,Default,,0000,0000,0000,,That's those two there.
Dialogue: 0,0:08:48.48,0:08:52.79,Default,,0000,0000,0000,,Then you have 5s2. 5s2.
Dialogue: 0,0:08:52.81,0:08:54.89,Default,,0000,0000,0000,,Then we had 4p6.
Dialogue: 0,0:08:54.90,0:08:57.05,Default,,0000,0000,0000,,That's over here.
Dialogue: 0,0:08:57.06,0:08:59.03,Default,,0000,0000,0000,,Then we had 3d10.
Dialogue: 0,0:08:59.05,0:09:02.46,Default,,0000,0000,0000,,Remember, 4 minus 1, so 3d10.
Dialogue: 0,0:09:02.47,0:09:04.48,Default,,0000,0000,0000,,And then you had 4s2.
Dialogue: 0,0:09:04.49,0:09:06.76,Default,,0000,0000,0000,,And you just keep going backwards like that.
Dialogue: 0,0:09:06.78,0:09:08.87,Default,,0000,0000,0000,,But what's nice about going backwards is you immediately know,
Dialogue: 0,0:09:08.89,0:09:11.16,Default,,0000,0000,0000,,OK, what electrons are in my highest energy shell?
Dialogue: 0,0:09:11.18,0:09:14.24,Default,,0000,0000,0000,,Well I have this five as the highest energy shell I'm at.
Dialogue: 0,0:09:14.26,0:09:17.45,Default,,0000,0000,0000,,And these two that I filled right there, those are
Dialogue: 0,0:09:17.47,0:09:20.66,Default,,0000,0000,0000,,actually the electrons in the highest energy shell.
Dialogue: 0,0:09:20.68,0:09:23.24,Default,,0000,0000,0000,,They're not the highest energy electrons. These are.
Dialogue: 0,0:09:23.25,0:09:24.68,Default,,0000,0000,0000,,But these are kind of the ones that have
Dialogue: 0,0:09:24.70,0:09:28.07,Default,,0000,0000,0000,,the highest probability of being furthest away from the nucleus.
Dialogue: 0,0:09:28.09,0:09:29.95,Default,,0000,0000,0000,,So these are the ones that are going to react.
Dialogue: 0,0:09:29.96,0:09:31.45,Default,,0000,0000,0000,,And these are the ones that matter
Dialogue: 0,0:09:31.47,0:09:33.10,Default,,0000,0000,0000,,for most chemistry purposes.
Dialogue: 0,0:09:33.11,0:09:35.18,Default,,0000,0000,0000,,And just a little touchpoint here,
Dialogue: 0,0:09:35.26,0:09:36.71,Default,,0000,0000,0000,,and this isn't covered a lot,
Dialogue: 0,0:09:36.73,0:09:39.78,Default,,0000,0000,0000,,but we like to think that electrons are filling these buckets,
Dialogue: 0,0:09:39.80,0:09:40.97,Default,,0000,0000,0000,,and they stay in these buckets.
Dialogue: 0,0:09:40.99,0:09:43.70,Default,,0000,0000,0000,,But once you fill up an atom with electrons,
Dialogue: 0,0:09:43.71,0:09:46.08,Default,,0000,0000,0000,,they're not just staying in this nice, well-behaved way.
Dialogue: 0,0:09:46.09,0:09:48.15,Default,,0000,0000,0000,,They're all jumping between orbitals,
Dialogue: 0,0:09:48.22,0:09:48.97,Default,,0000,0000,0000,,and mixing together,
Dialogue: 0,0:09:48.99,0:09:51.13,Default,,0000,0000,0000,,and doing all sorts of crazy, unpredictable things.
Dialogue: 0,0:09:51.14,0:09:54.73,Default,,0000,0000,0000,,But this method is what allows us to at least get a sense
Dialogue: 0,0:09:54.75,0:09:56.64,Default,,0000,0000,0000,,of what's happening in the electron.
Dialogue: 0,0:09:56.66,0:09:59.45,Default,,0000,0000,0000,,For most purposes, they do tend to
Dialogue: 0,0:09:59.49,0:10:00.92,Default,,0000,0000,0000,,react or behave in ways
Dialogue: 0,0:10:01.00,0:10:03.51,Default,,0000,0000,0000,,that these orbitals kind of stay to themselves.
Dialogue: 0,0:10:03.53,0:10:06.44,Default,,0000,0000,0000,,But anyway, the main point of here is really just to
Dialogue: 0,0:10:06.46,0:10:07.84,Default,,0000,0000,0000,,teach you how to do electron configurations,
Dialogue: 0,0:10:07.86,0:10:09.89,Default,,0000,0000,0000,,because that's really useful for later on
Dialogue: 0,0:10:09.90,0:10:11.98,Default,,0000,0000,0000,,knowing how things will interact.
Dialogue: 0,0:10:12.00,0:10:13.39,Default,,0000,0000,0000,,And what's especially useful is to know
Dialogue: 0,0:10:13.41,0:10:15.29,Default,,0000,0000,0000,,what electrons are in the outermost shell,
Dialogue: 0,0:10:15.31,0:10:16.84,Default,,0000,0000,0000,,or what are the valence electrons.