1 00:00:00,650 --> 00:00:02,420 In the last few videos we learned that 2 00:00:02,440 --> 00:00:05,300 the configuration of electrons in an atom 3 00:00:05,340 --> 00:00:08,090 aren't in a simple, classical, 4 00:00:08,170 --> 00:00:10,460 Newtonian orbit configuration. 5 00:00:10,500 --> 00:00:12,210 And that's the Bohr model of the electron. 6 00:00:12,220 --> 00:00:13,840 And I'll keep reviewing it, 7 00:00:13,890 --> 00:00:14,870 just because I think it's an important point. 8 00:00:14,890 --> 00:00:16,040 If that's the nucleus, remember, 9 00:00:16,050 --> 00:00:17,800 it's just a tiny, tiny, tiny dot 10 00:00:17,820 --> 00:00:21,460 if you think about the entire volume of the actual atom. 11 00:00:21,570 --> 00:00:24,590 And instead of the electron being in orbits around it, 12 00:00:24,610 --> 00:00:29,100 which would be how a planet orbits the sun. 13 00:00:29,110 --> 00:00:30,990 Instead of being in orbits around it, 14 00:00:31,030 --> 00:00:33,470 it's described by orbitals, 15 00:00:33,480 --> 00:00:36,570 which are these probability density functions. 16 00:00:36,590 --> 00:00:39,750 So an orbital-- let's say that's the nucleus 17 00:00:39,770 --> 00:00:42,170 it would describe, 18 00:00:42,190 --> 00:00:45,490 if you took any point in space around the nucleus, 19 00:00:45,500 --> 00:00:48,410 the probability of finding the electron. 20 00:00:48,420 --> 00:00:53,790 So actually, in any volume of space around the nucleus, 21 00:00:53,810 --> 00:00:54,780 it would tell you the probability 22 00:00:54,790 --> 00:00:56,930 of finding the electron within that volume. 23 00:00:56,950 --> 00:00:58,760 And so if you were to just take 24 00:00:58,770 --> 00:01:00,370 a bunch of snapshots of electrons 25 00:01:00,380 --> 00:01:03,160 -- let's say in the 1s orbital. 26 00:01:03,170 --> 00:01:05,430 And that's what the 1s orbital looks like. 27 00:01:05,450 --> 00:01:08,510 You can barely see it there, 28 00:01:08,520 --> 00:01:10,970 but it's a sphere around the nucleus, 29 00:01:10,990 --> 00:01:14,110 and that's the lowest energy state that an electron can be in. 30 00:01:14,120 --> 00:01:16,710 If you were to just take a number of snapshots of electrons. 31 00:01:16,730 --> 00:01:21,370 Let's say you were to take a number of snapshots of helium, 32 00:01:21,380 --> 00:01:22,700 which has two electrons. 33 00:01:22,720 --> 00:01:25,760 Both of them are in the 1s orbital. 34 00:01:25,780 --> 00:01:26,770 It would look like this. 35 00:01:26,800 --> 00:01:28,470 If you took one snapshot, maybe it'll be there, 36 00:01:28,480 --> 00:01:30,490 the next snapshot, maybe the electron is there. 37 00:01:30,530 --> 00:01:32,310 Then the electron is there. 38 00:01:32,330 --> 00:01:34,120 Then the electron is there. Then it's there. 39 00:01:34,140 --> 00:01:35,320 And if you kept doing the snapshots, 40 00:01:35,370 --> 00:01:37,960 you would have a bunch of them really close. 41 00:01:37,970 --> 00:01:40,940 And then it gets a little bit sparser as you get out, 42 00:01:40,960 --> 00:01:44,940 as you get further and further out away from the electron. 43 00:01:44,990 --> 00:01:47,190 But as you see, you're much more likely 44 00:01:47,210 --> 00:01:50,680 to find the electron close to 45 00:01:50,700 --> 00:01:54,580 the center of the atom than further out. 46 00:01:54,630 --> 00:01:56,150 Although you might have had an observation with the electron 47 00:01:56,170 --> 00:01:58,660 sitting all the way out there, or sitting over here. 48 00:01:58,680 --> 00:01:59,810 So it really could have been anywhere, 49 00:01:59,830 --> 00:02:01,490 but if you take multiple observations, 50 00:02:01,510 --> 00:02:04,910 you'll see what that probability function is describing. 51 00:02:04,920 --> 00:02:07,250 It's saying look, there's a much lower probability of 52 00:02:07,270 --> 00:02:11,740 finding the electron out in this little cube of volume space 53 00:02:11,760 --> 00:02:14,930 than it is in this little cube of volume space. 54 00:02:14,950 --> 00:02:16,660 And when you see these diagrams 55 00:02:16,670 --> 00:02:18,620 that draw this orbital like this. 56 00:02:18,640 --> 00:02:23,820 Let's say they draw it like a shell, like a sphere. 57 00:02:23,830 --> 00:02:25,590 And I'll try to make it look three-dimensional. 58 00:02:25,600 --> 00:02:27,290 So let's say this is the outside of it, 59 00:02:27,310 --> 00:02:29,980 and the nucleus is sitting some place on the inside. 60 00:02:29,990 --> 00:02:32,760 They're just saying -- they just draw a cut-off 61 00:02:32,780 --> 00:02:35,010 -- where can I find the electron 90% of the time? 62 00:02:35,020 --> 00:02:36,240 So they're saying, OK, I can find the electron 63 00:02:36,260 --> 00:02:38,970 90% of the time within this circle, 64 00:02:38,990 --> 00:02:40,700 if I were to do the cross-section. 65 00:02:40,710 --> 00:02:42,200 But every now and then the electron 66 00:02:42,210 --> 00:02:44,070 can show up outside of that, right? 67 00:02:44,090 --> 00:02:45,040 Because it's all probabilistic. 68 00:02:45,060 --> 00:02:46,370 So this can still happen. 69 00:02:46,390 --> 00:02:47,720 You can still find the electron 70 00:02:47,740 --> 00:02:51,120 if this is the orbital we're talking about out here. 71 00:02:51,140 --> 00:02:52,270 Right? 72 00:02:52,290 --> 00:02:54,180 And then we, in the last video, we said, 73 00:02:54,200 --> 00:02:57,030 OK, the electrons fill up the orbitals 74 00:02:57,050 --> 00:03:05,950 from lowest energy state to high energy state. 75 00:03:05,970 --> 00:03:09,530 You could imagine it. If I'm playing Tetris-- 76 00:03:09,540 --> 00:03:10,930 well I don't know if Tetris is the thing-- 77 00:03:10,950 --> 00:03:14,450 but if I'm stacking cubes, I lay out cubes from low energy, 78 00:03:14,470 --> 00:03:15,440 if this is the floor, 79 00:03:15,460 --> 00:03:17,720 I put the first cube at the lowest energy state. 80 00:03:17,730 --> 00:03:21,000 And let's say I could put the second cube 81 00:03:21,020 --> 00:03:21,930 at a low energy state here. 82 00:03:21,950 --> 00:03:27,630 But I only have this much space to work with. 83 00:03:27,650 --> 00:03:28,750 So I have to put the third cube 84 00:03:28,770 --> 00:03:30,490 at the next highest energy state. 85 00:03:30,510 --> 00:03:32,030 In this case our energy would 86 00:03:32,050 --> 00:03:33,980 be described as potential energy, right? 87 00:03:34,000 --> 00:03:36,350 This is just a classical, Newtonian physics example. 88 00:03:36,370 --> 00:03:39,540 But that's the same idea with electrons. 89 00:03:39,560 --> 00:03:44,460 Once I have two electrons in this 1s orbital 90 00:03:44,470 --> 00:03:49,390 -- so let's say the electron configuration of helium is 1s2 91 00:03:49,410 --> 00:03:52,390 -- the third electron I can't put there anymore, 92 00:03:52,400 --> 00:03:54,190 because there's only room for two electrons. 93 00:03:54,210 --> 00:03:57,270 The way I think about it is these two electrons are now 94 00:03:57,290 --> 00:03:59,000 going to repel the third one I want to add. 95 00:03:59,020 --> 00:04:02,410 So then I have to go to the 2s orbital. 96 00:04:02,420 --> 00:04:06,020 And now if I were to plot the 2s orbital on top of this one, 97 00:04:06,030 --> 00:04:07,350 it would look something like this, 98 00:04:07,360 --> 00:04:08,560 where I have a high probability 99 00:04:08,580 --> 00:04:12,010 of finding the electrons in this shell 100 00:04:12,030 --> 00:04:19,050 that's essentially around the 1s orbital, right? 101 00:04:19,070 --> 00:04:23,230 So right now, if maybe I'm dealing with lithium right now. 102 00:04:23,250 --> 00:04:24,650 So I only have one extra electron. 103 00:04:24,660 --> 00:04:25,960 So this one extra electron, 104 00:04:25,970 --> 00:04:29,250 that might be where I observed that extra electron. 105 00:04:29,270 --> 00:04:30,980 But every now and then it could show up there, 106 00:04:31,000 --> 00:04:32,840 it could show up there, it could show up there, 107 00:04:32,860 --> 00:04:34,320 but the high probability is there. 108 00:04:34,340 --> 00:04:37,110 So when you say where is it going to be 90% of the time? 109 00:04:37,130 --> 00:04:39,730 It'll be like this shell that's around the center. 110 00:04:39,750 --> 00:04:40,820 Remember, when it's three-dimensional 111 00:04:40,840 --> 00:04:42,060 you would kind of cover it up. 112 00:04:42,080 --> 00:04:42,910 So it would be this shell. 113 00:04:42,950 --> 00:04:45,170 So that's what they drew here. 114 00:04:45,180 --> 00:04:47,880 They do the 1s. 115 00:04:47,900 --> 00:04:49,060 It's just a red shell. 116 00:04:49,080 --> 00:04:50,490 And then the 2s. 117 00:04:50,510 --> 00:04:53,580 The second energy shell is just this blue shell over it. 118 00:04:53,600 --> 00:04:55,630 And you can see it a little bit better in, actually, 119 00:04:55,650 --> 00:04:57,900 the higher energy orbits, the higher energy shells, 120 00:04:57,920 --> 00:05:02,280 where the seventh s energy shell is this red area. 121 00:05:02,290 --> 00:05:04,490 Then you have the blue area, then the red, and the blue. 122 00:05:04,500 --> 00:05:05,900 And so I think you get the idea 123 00:05:05,910 --> 00:05:07,370 that each of those are energy shells. 124 00:05:07,390 --> 00:05:09,100 So you kind of keep overlaying 125 00:05:09,120 --> 00:05:11,040 the s energy orbitals around each other. 126 00:05:11,690 --> 00:05:14,360 But you probably see this other stuff here. 127 00:05:14,380 --> 00:05:15,830 And the general principle, remember, 128 00:05:15,850 --> 00:05:18,660 is that the electrons fill up the orbital 129 00:05:18,680 --> 00:05:21,300 from lowest energy orbital to higher energy orbital. 130 00:05:21,310 --> 00:05:24,920 So the first one that's filled up is the 1s. 131 00:05:24,940 --> 00:05:26,570 This is the 1. 132 00:05:26,590 --> 00:05:27,400 This is the s. 133 00:05:27,410 --> 00:05:28,530 So this is the 1s. 134 00:05:28,550 --> 00:05:29,980 It can fit two electrons. 135 00:05:30,000 --> 00:05:32,460 Then the next one that's filled up is 2s. 136 00:05:32,480 --> 00:05:34,880 It can fill two more electrons. 137 00:05:34,900 --> 00:05:37,910 And then the next one, and this is where it gets interesting, 138 00:05:37,920 --> 00:05:40,210 you fill up the 2p orbital. 139 00:05:40,220 --> 00:05:42,460 2p orbital. 140 00:05:42,480 --> 00:05:44,180 That's this, right here. 141 00:05:44,200 --> 00:05:46,870 2p orbitals. 142 00:05:46,890 --> 00:05:49,420 And notice the p orbitals have something, 143 00:05:49,440 --> 00:05:53,820 p sub z, p sub x, p sub y. 144 00:05:53,840 --> 00:05:55,530 What does that mean? 145 00:05:55,540 --> 00:05:57,250 Well, if you look at the p-orbitals, 146 00:05:57,270 --> 00:05:58,830 they have these dumbbell shapes. 147 00:05:58,850 --> 00:06:00,960 They look a little unnatural, but I think in future videos 148 00:06:00,980 --> 00:06:03,940 we'll show you how they're analogous to standing waves. 149 00:06:03,960 --> 00:06:06,560 But if you look at these, there's three ways 150 00:06:06,580 --> 00:06:08,180 that you can configure these dumbbells. 151 00:06:08,200 --> 00:06:09,850 One in the z direction, up and down. 152 00:06:09,860 --> 00:06:11,960 One in the x direction, left or right. 153 00:06:11,980 --> 00:06:13,710 And then one in the y direction, 154 00:06:13,730 --> 00:06:16,030 this way, forward and backwards, right? 155 00:06:16,050 --> 00:06:17,650 And so if you were to draw-- 156 00:06:17,670 --> 00:06:20,600 let's say you wanted to draw the p-orbitals. 157 00:06:20,620 --> 00:06:22,780 So this is what you fill next. 158 00:06:22,800 --> 00:06:24,360 And actually, you fill one electron here, 159 00:06:24,380 --> 00:06:26,530 another electron here, then another electron there. 160 00:06:26,550 --> 00:06:28,230 Then you fill another electron, 161 00:06:28,250 --> 00:06:30,110 and we'll talk about spin and things like that in the future. 162 00:06:30,130 --> 00:06:32,660 But, there, there, and there. 163 00:06:32,680 --> 00:06:34,110 And that's actually called Hund's rule. 164 00:06:34,130 --> 00:06:36,150 Maybe I'll do a whole video on Hund's rule, 165 00:06:36,160 --> 00:06:39,770 but that's not relevant to a first-year chemistry lecture. 166 00:06:39,790 --> 00:06:42,460 But it fills in that order, and once again, 167 00:06:42,480 --> 00:06:46,580 I want you to have the intuition of what this would look like. 168 00:06:46,600 --> 00:06:47,510 Look. 169 00:06:47,530 --> 00:06:50,140 I should put look in quotation marks, 170 00:06:50,160 --> 00:06:52,230 because it's very abstract. 171 00:06:52,240 --> 00:06:54,700 But if you wanted to visualize the p orbitals-- 172 00:06:54,710 --> 00:06:56,380 let's say we're looking at 173 00:06:56,390 --> 00:07:00,530 the electron configuration for, let's say, carbon. 174 00:07:01,840 --> 00:07:04,320 So the electron configuration for carbon, 175 00:07:04,340 --> 00:07:09,600 the first two electrons go into, so, 1s1, 1s2. 176 00:07:09,610 --> 00:07:13,650 So then it fills-- sorry, you can't see everything. 177 00:07:13,670 --> 00:07:18,040 So it fills the 1s2, so carbon's configuration. 178 00:07:20,170 --> 00:07:23,310 It fills 1s1 then 1s2. 179 00:07:23,320 --> 00:07:26,530 And this is just the configuration for helium. 180 00:07:26,550 --> 00:07:28,440 And then it goes to the second shell, 181 00:07:28,460 --> 00:07:30,970 which is the second period, right? 182 00:07:30,990 --> 00:07:32,290 That's why it's called the periodic table. 183 00:07:32,310 --> 00:07:34,520 We'll talk about periods and groups in the future. 184 00:07:34,540 --> 00:07:35,940 And then you go here. 185 00:07:35,960 --> 00:07:38,620 So this is filling the 2s. 186 00:07:38,640 --> 00:07:40,210 We're in the second period right here. 187 00:07:40,230 --> 00:07:41,960 That's the second period. 188 00:07:41,980 --> 00:07:43,100 One, two. 189 00:07:43,120 --> 00:07:45,920 Have to go off, so you can see everything. 190 00:07:45,940 --> 00:07:47,270 So it fills these two. 191 00:07:47,290 --> 00:07:50,140 So 2s2. 192 00:07:50,150 --> 00:07:52,470 And then it starts filling up the p orbitals. 193 00:07:52,490 --> 00:07:56,320 So then it starts filling 1p and then 2p. 194 00:07:56,340 --> 00:08:01,720 And we're still on the second shell, so 2s2, 2p2. 195 00:08:01,740 --> 00:08:04,080 So the question is what would this look like 196 00:08:04,090 --> 00:08:07,130 if we just wanted to visualize this orbital 197 00:08:07,150 --> 00:08:08,850 right here, the p orbitals? 198 00:08:08,870 --> 00:08:11,300 So we have two electrons. 199 00:08:11,320 --> 00:08:14,610 So one electron is going to be in a-- Let's say if this is, 200 00:08:14,630 --> 00:08:16,660 I'll try to draw some axes. 201 00:08:16,680 --> 00:08:18,940 That's too thin. 202 00:08:20,190 --> 00:08:25,710 So if I draw a three-dimensional volume kind of axes. 203 00:08:28,430 --> 00:08:30,710 If I were to make a bunch of observations of, say, 204 00:08:30,720 --> 00:08:33,730 one of the electrons in the p orbitals, 205 00:08:33,750 --> 00:08:35,600 let's say in the pz dimension, 206 00:08:35,620 --> 00:08:38,020 sometimes it might be here, sometimes it might be there, 207 00:08:38,040 --> 00:08:39,020 sometimes it might be there. 208 00:08:39,040 --> 00:08:45,260 And then if you keep taking a bunch of observations, 209 00:08:46,510 --> 00:08:51,170 you're going to have something that looks like this bell shape, 210 00:08:51,190 --> 00:08:53,660 this barbell shape right there. 211 00:08:53,670 --> 00:08:55,730 And then for the other electron 212 00:08:55,750 --> 00:08:58,080 that's maybe in the x direction, 213 00:08:58,100 --> 00:09:00,300 you make a bunch of observations. 214 00:09:00,320 --> 00:09:01,410 Let me do it in a different, 215 00:09:01,430 --> 00:09:03,420 in a noticeably different, color. 216 00:09:03,440 --> 00:09:04,600 It will look like this. 217 00:09:04,610 --> 00:09:06,740 You take a bunch of observations, and you say, 218 00:09:06,760 --> 00:09:09,370 wow, it's a lot more likely to find that 219 00:09:09,390 --> 00:09:12,710 electron in kind of the dumbell, in that dumbbell shape. 220 00:09:12,730 --> 00:09:13,640 But you could find it out there. 221 00:09:13,660 --> 00:09:14,550 You could find it there. 222 00:09:14,570 --> 00:09:15,420 You could find it there. 223 00:09:15,440 --> 00:09:17,650 This is just a much higher probability of 224 00:09:17,660 --> 00:09:19,420 finding it in here than out here. 225 00:09:19,430 --> 00:09:23,520 And that's the best way I can think of to visualize it. 226 00:09:23,540 --> 00:09:25,220 Now what we were doing here, 227 00:09:25,230 --> 00:09:27,570 this is called an electron configuration. 228 00:09:27,590 --> 00:09:30,750 And the way to do it-- and there's multiple ways that are 229 00:09:30,770 --> 00:09:33,170 taught in chemistry class, but the way I like to do it 230 00:09:33,190 --> 00:09:40,660 -- is you take the periodic table and you say, these groups, 231 00:09:40,680 --> 00:09:42,740 and when I say groups I mean the columns, 232 00:09:42,750 --> 00:09:49,010 these are going to fill the s subshell or the s orbitals. 233 00:09:51,180 --> 00:09:53,460 You can just write s up here, just right there. 234 00:09:53,480 --> 00:09:57,930 These over here are going to fill the p orbitals. 235 00:09:59,630 --> 00:10:01,790 Actually, let me take helium out of the picture. 236 00:10:01,810 --> 00:10:03,190 The p orbitals. 237 00:10:03,210 --> 00:10:04,010 Let me just do that. 238 00:10:04,030 --> 00:10:05,900 Let me take helium out of the picture. 239 00:10:05,920 --> 00:10:07,580 These take the p orbitals. 240 00:10:07,600 --> 00:10:09,670 And actually, for the sake of figuring out these, 241 00:10:09,690 --> 00:10:12,380 you should take helium and throw it right over there. 242 00:10:12,390 --> 00:10:13,230 Right? 243 00:10:13,250 --> 00:10:14,610 The periodic table is just a way 244 00:10:14,630 --> 00:10:16,510 to organize things so it makes sense, 245 00:10:16,520 --> 00:10:18,420 but in terms of trying to figure out orbitals, 246 00:10:18,440 --> 00:10:19,900 you could take helium. 247 00:10:19,910 --> 00:10:20,900 Let me do that. 248 00:10:20,920 --> 00:10:22,920 The magic of computers. 249 00:10:22,940 --> 00:10:27,740 Cut it out, and then let me paste it right over there. 250 00:10:27,760 --> 00:10:29,620 Right? 251 00:10:29,640 --> 00:10:33,270 And now you see that helium, you get 1s and then you get 2s, 252 00:10:33,280 --> 00:10:34,690 so helium's configuration is 253 00:10:34,700 --> 00:10:38,150 -- Sorry, you get 1s1, then 1s2. 254 00:10:38,160 --> 00:10:40,100 We're in the first energy shell. 255 00:10:40,110 --> 00:10:41,650 Right? 256 00:10:41,660 --> 00:10:50,500 So the configuration of hydrogen is 1s1. 257 00:10:50,520 --> 00:10:52,020 You only have one electron 258 00:10:52,040 --> 00:10:57,680 in the s subshell of the first energy shell. 259 00:10:58,260 --> 00:11:01,490 The configuration of helium is 1s2. 260 00:11:02,280 --> 00:11:06,300 And then you start filling the second energy shell. 261 00:11:06,320 --> 00:11:12,200 The configuration of lithium is 1s2. 262 00:11:12,220 --> 00:11:13,580 That's where the first two electrons go. 263 00:11:13,590 --> 00:11:18,140 And then the third one goes into 2s1, right? 264 00:11:18,160 --> 00:11:20,570 And then I think you start to see the pattern. 265 00:11:20,590 --> 00:11:24,330 And then when you go to nitrogen you say, 266 00:11:24,350 --> 00:11:29,170 OK, it has three in the p sub-orbital. 267 00:11:29,190 --> 00:11:31,510 So you can almost start backwards, right? 268 00:11:31,530 --> 00:11:36,230 So we're in period two, right? 269 00:11:36,240 --> 00:11:38,870 So this is 2p3. 270 00:11:39,630 --> 00:11:40,510 Let me write that down. 271 00:11:40,530 --> 00:11:44,300 So I could write that down first. 2p3. 272 00:11:45,020 --> 00:11:47,720 So that's where the last three electrons 273 00:11:47,740 --> 00:11:48,930 go into the p orbital. 274 00:11:48,940 --> 00:11:57,860 Then it'll have these two that go into the 2s2 orbital. 275 00:11:57,870 --> 00:12:01,390 And then the first two, or the electrons 276 00:12:01,410 --> 00:12:06,130 in the lowest energy state, will be 1s2. 277 00:12:06,150 --> 00:12:07,890 So this is the electron configuration, 278 00:12:07,910 --> 00:12:10,730 right here, of nitrogen. 279 00:12:11,810 --> 00:12:15,160 And just to make sure you did your configuration right, 280 00:12:15,180 --> 00:12:17,180 what you do is you count the number of electrons. 281 00:12:17,200 --> 00:12:20,120 So 2 plus 2 is 4 plus 3 is 7. 282 00:12:20,130 --> 00:12:22,350 And we're talking about neutral atoms, 283 00:12:22,370 --> 00:12:24,920 so the electrons should equal the number of protons. 284 00:12:24,940 --> 00:12:27,440 The atomic number is the number of protons. 285 00:12:27,450 --> 00:12:28,460 So we're good. 286 00:12:28,470 --> 00:12:30,590 Seven protons. So this is, so far, 287 00:12:30,610 --> 00:12:32,620 when we're dealing just with the s's and the p's, 288 00:12:32,630 --> 00:12:33,980 this is pretty straightforward. 289 00:12:34,000 --> 00:12:38,310 And if I wanted to figure out the configuration of silicon, 290 00:12:39,970 --> 00:12:42,010 right there, what is it? 291 00:12:42,030 --> 00:12:43,840 Well, we're in the third period. 292 00:12:43,850 --> 00:12:46,070 One, two, three. 293 00:12:46,090 --> 00:12:47,670 That's just the third row. 294 00:12:47,690 --> 00:12:50,090 And this is the p-block right here. 295 00:12:50,110 --> 00:12:52,750 So this is the second row in the p-block, right? 296 00:12:52,770 --> 00:12:54,940 One, two, three, four, five, six. 297 00:12:54,960 --> 00:12:56,170 Right. 298 00:12:56,190 --> 00:12:57,370 We're in the second row of the p-block, 299 00:12:57,390 --> 00:13:03,080 so we start off with 3p2. 300 00:13:03,980 --> 00:13:08,310 And then we have 3s2. 301 00:13:08,330 --> 00:13:10,840 And then it filled up all of this p-block over here. 302 00:13:10,850 --> 00:13:14,470 So it's 2p6. 303 00:13:14,490 --> 00:13:16,980 And then here, 2s2. 304 00:13:17,000 --> 00:13:19,330 And then, of course, it filled up at the first shell 305 00:13:19,340 --> 00:13:20,870 before it could fill up these other shells. 306 00:13:20,890 --> 00:13:21,960 So, 1s2. 307 00:13:21,980 --> 00:13:26,660 So this is the electron configuration for silicon. 308 00:13:26,670 --> 00:13:29,550 And we can confirm that we should have 14 electrons. 309 00:13:29,570 --> 00:13:33,280 2 plus 2 is 4, plus 6 is 10. 310 00:13:33,970 --> 00:13:38,010 10 plus 2 is 12 plus 2 more is 14. 311 00:13:38,030 --> 00:13:40,020 So we're good with silicon. 312 00:13:40,040 --> 00:13:42,390 I think I'm running low on time right now, 313 00:13:42,410 --> 00:13:44,690 so in the next video we'll start addressing what happens 314 00:13:44,700 --> 00:13:47,840 when you go to these elements, or the d-block. 315 00:13:47,850 --> 00:13:50,140 And you can kind of already guess what happens. 316 00:13:50,160 --> 00:13:54,950 We're going to start filling up these d orbitals here 317 00:13:54,970 --> 00:13:56,540 that have even more bizarre shapes. 318 00:13:56,550 --> 00:13:59,270 And the way I think about this, not to waste too much time, 319 00:13:59,290 --> 00:14:03,920 is that as you go further and further out from the nucleus, 320 00:14:03,940 --> 00:14:06,780 there's more space in between the lower energy orbitals 321 00:14:06,800 --> 00:14:10,170 to fill in more of these bizarro-shaped orbitals. 322 00:14:10,190 --> 00:14:12,800 But these are kind of the balance -- 323 00:14:12,820 --> 00:14:14,830 I will talk about standing waves in the future 324 00:14:14,840 --> 00:14:16,740 -- but these are kind of a balance between trying to 325 00:14:16,760 --> 00:14:18,690 get close to the nucleus 326 00:14:18,710 --> 00:14:20,360 and the proton and those positive charges, 327 00:14:20,370 --> 00:14:22,310 because the electron charges are attracted to them, 328 00:14:22,320 --> 00:14:25,250 while at the same time avoiding the other electron charges, 329 00:14:25,270 --> 00:14:27,820 or at least their mass distribution functions. 330 00:14:27,840 --> 00:14:29,250 Anyway, see you in the next video.