[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:00.66,Default,,0000,0000,0000,,
Dialogue: 0,0:00:00.66,0:00:03.42,Default,,0000,0000,0000,,Throughout our journey through\Nchemistry so far, we've
Dialogue: 0,0:00:03.42,0:00:08.81,Default,,0000,0000,0000,,touched on the interactions\Nbetween molecules, metal
Dialogue: 0,0:00:08.81,0:00:11.29,Default,,0000,0000,0000,,molecules, how they attract each\Nother because of the sea
Dialogue: 0,0:00:11.29,0:00:12.66,Default,,0000,0000,0000,,of electrons and water\Nmolecules.
Dialogue: 0,0:00:12.66,0:00:16.54,Default,,0000,0000,0000,,But I think it's good to have a\Ngeneral discussion about all
Dialogue: 0,0:00:16.54,0:00:19.10,Default,,0000,0000,0000,,of the different types of\Nmolecular interactions and
Dialogue: 0,0:00:19.10,0:00:21.86,Default,,0000,0000,0000,,what it means for the boiling\Npoints or the melting points
Dialogue: 0,0:00:21.86,0:00:22.89,Default,,0000,0000,0000,,of a substance.
Dialogue: 0,0:00:22.89,0:00:24.87,Default,,0000,0000,0000,,So I'll start with the weakest.\NLet's say I had a
Dialogue: 0,0:00:24.87,0:00:26.12,Default,,0000,0000,0000,,bunch of helium.
Dialogue: 0,0:00:26.12,0:00:30.10,Default,,0000,0000,0000,,Helium, you know, I'll just draw\Nit as helium atoms. We'll
Dialogue: 0,0:00:30.10,0:00:33.15,Default,,0000,0000,0000,,look in the Periodic Table, and\Nwhat I'm going to do now
Dialogue: 0,0:00:33.15,0:00:35.36,Default,,0000,0000,0000,,with helium I could do with\Nany of the noble gases.
Dialogue: 0,0:00:35.36,0:00:37.86,Default,,0000,0000,0000,,Because the point is that\Nnoble gases are happy.
Dialogue: 0,0:00:37.86,0:00:39.28,Default,,0000,0000,0000,,Their outer orbital is filled.
Dialogue: 0,0:00:39.28,0:00:41.59,Default,,0000,0000,0000,,Let's say, neon or helium--\Nlet me do neon, actually,
Dialogue: 0,0:00:41.59,0:00:45.21,Default,,0000,0000,0000,,because neon has a full eight\Nin its orbital so we could
Dialogue: 0,0:00:45.21,0:00:49.75,Default,,0000,0000,0000,,write neon like neon and\Nit's completely happy.
Dialogue: 0,0:00:49.75,0:00:53.60,Default,,0000,0000,0000,,It's completely satisfied\Nwith itself.
Dialogue: 0,0:00:53.60,0:00:57.95,Default,,0000,0000,0000,,And so in a world where it's\Ncompletely satisfied, there's
Dialogue: 0,0:00:57.95,0:01:00.63,Default,,0000,0000,0000,,no obvious reason just yet-- I'm\Ngoing to touch on a reason
Dialogue: 0,0:01:00.63,0:01:02.85,Default,,0000,0000,0000,,why it should be-- if these\Nelectrons are evenly
Dialogue: 0,0:01:02.85,0:01:04.92,Default,,0000,0000,0000,,distributed around these\Natoms, then these are
Dialogue: 0,0:01:04.92,0:01:08.04,Default,,0000,0000,0000,,completely neutral atoms. They\Ndon't want to bond with each
Dialogue: 0,0:01:08.04,0:01:11.08,Default,,0000,0000,0000,,other or do anything else, so\Nthey should just float around
Dialogue: 0,0:01:11.08,0:01:13.31,Default,,0000,0000,0000,,and there's no reason for them\Nto be attracted to each other
Dialogue: 0,0:01:13.31,0:01:15.10,Default,,0000,0000,0000,,or not attracted\Nto each other.
Dialogue: 0,0:01:15.10,0:01:18.37,Default,,0000,0000,0000,,But it turns out that neon does\Nhave a liquid state, if
Dialogue: 0,0:01:18.37,0:01:21.23,Default,,0000,0000,0000,,you get cold enough, and so the\Nfact that it has a liquid
Dialogue: 0,0:01:21.23,0:01:26.82,Default,,0000,0000,0000,,state means that there must be\Nsome force that's making the
Dialogue: 0,0:01:26.82,0:01:31.06,Default,,0000,0000,0000,,neon atoms attracted to each\Nother, some force out there.
Dialogue: 0,0:01:31.06,0:01:33.26,Default,,0000,0000,0000,,Because it's in a very cold\Nstate, because for the most
Dialogue: 0,0:01:33.26,0:01:35.43,Default,,0000,0000,0000,,part, there is not a lot of\Nforce that attracts them so
Dialogue: 0,0:01:35.43,0:01:37.21,Default,,0000,0000,0000,,it'll be a gas at most\Ntemperatures.
Dialogue: 0,0:01:37.21,0:01:40.57,Default,,0000,0000,0000,,But if you get really cold, you\Ncan get a very weak force
Dialogue: 0,0:01:40.57,0:01:44.13,Default,,0000,0000,0000,,that starts to connect or makes\Nthe neon molecules want
Dialogue: 0,0:01:44.13,0:01:46.24,Default,,0000,0000,0000,,to get towards each other.
Dialogue: 0,0:01:46.24,0:01:49.16,Default,,0000,0000,0000,,And that force comes out of\Nthe reality that we talked
Dialogue: 0,0:01:49.16,0:01:53.95,Default,,0000,0000,0000,,about early on that electrons\Nare not in a fixed, uniform
Dialogue: 0,0:01:53.95,0:01:54.99,Default,,0000,0000,0000,,orbit around things.
Dialogue: 0,0:01:54.99,0:01:56.24,Default,,0000,0000,0000,,They're probablistic.
Dialogue: 0,0:01:56.24,0:02:00.42,Default,,0000,0000,0000,,And if we imagine, let me say\Nneon now, instead of drawing
Dialogue: 0,0:02:00.42,0:02:04.09,Default,,0000,0000,0000,,these nice and neat valence\Ndot electrons like that,
Dialogue: 0,0:02:04.09,0:02:07.76,Default,,0000,0000,0000,,instead, I can kind of draw\Nits electrons as-- it's a
Dialogue: 0,0:02:07.76,0:02:11.06,Default,,0000,0000,0000,,probability cloud and it's\Nwhat neon's atomic
Dialogue: 0,0:02:11.06,0:02:12.42,Default,,0000,0000,0000,,configuration is.
Dialogue: 0,0:02:12.42,0:02:18.63,Default,,0000,0000,0000,,1s2 and it's outer orbital\Nis 2s2 2p6, right?
Dialogue: 0,0:02:18.63,0:02:20.55,Default,,0000,0000,0000,,So it's highest energy electron,\Nso, you know, it'll
Dialogue: 0,0:02:20.55,0:02:21.58,Default,,0000,0000,0000,,look-- I don't know.
Dialogue: 0,0:02:21.58,0:02:24.56,Default,,0000,0000,0000,,It has the 2s shell.
Dialogue: 0,0:02:24.56,0:02:28.11,Default,,0000,0000,0000,,The 1s shell is inside of that\Nand it has the p-orbitals.
Dialogue: 0,0:02:28.11,0:02:32.16,Default,,0000,0000,0000,,The p-orbitals look like that\Nin different dimensions.
Dialogue: 0,0:02:32.16,0:02:33.13,Default,,0000,0000,0000,,That's not the point.
Dialogue: 0,0:02:33.13,0:02:36.68,Default,,0000,0000,0000,,And then you have another neon\Natom and these are-- and I'm
Dialogue: 0,0:02:36.68,0:02:38.55,Default,,0000,0000,0000,,just drawing the probability\Ndistribution.
Dialogue: 0,0:02:38.55,0:02:40.35,Default,,0000,0000,0000,,I'm not trying to\Ndraw a rabbit.
Dialogue: 0,0:02:40.35,0:02:42.25,Default,,0000,0000,0000,,But I think you get the point.
Dialogue: 0,0:02:42.25,0:02:46.62,Default,,0000,0000,0000,,Watch the electron configuration\Nvideos if you
Dialogue: 0,0:02:46.62,0:02:49.44,Default,,0000,0000,0000,,want more on this, but the idea\Nbehind these probability
Dialogue: 0,0:02:49.44,0:02:53.39,Default,,0000,0000,0000,,distributions is that the\Nelectrons could be anywhere.
Dialogue: 0,0:02:53.39,0:02:54.96,Default,,0000,0000,0000,,There could be a moment in time\Nwhen all the electrons
Dialogue: 0,0:02:54.96,0:02:55.94,Default,,0000,0000,0000,,are out over here.
Dialogue: 0,0:02:55.94,0:02:57.33,Default,,0000,0000,0000,,There could be a moment in time\Nwhere all the electrons
Dialogue: 0,0:02:57.33,0:02:57.81,Default,,0000,0000,0000,,are over here.
Dialogue: 0,0:02:57.81,0:02:59.51,Default,,0000,0000,0000,,Same thing for this neon atom.
Dialogue: 0,0:02:59.51,0:03:01.59,Default,,0000,0000,0000,,If you think about it, out\Nof all of the possible
Dialogue: 0,0:03:01.59,0:03:04.69,Default,,0000,0000,0000,,configurations, let's say we\Nhave these two neon atoms,
Dialogue: 0,0:03:04.69,0:03:07.29,Default,,0000,0000,0000,,there's actually a very low\Nlikelihood that they're going
Dialogue: 0,0:03:07.29,0:03:09.06,Default,,0000,0000,0000,,to be completely evenly\Ndistributed.
Dialogue: 0,0:03:09.06,0:03:11.76,Default,,0000,0000,0000,,
Dialogue: 0,0:03:11.76,0:03:13.77,Default,,0000,0000,0000,,There's many more scenarios\Nwhere the electron
Dialogue: 0,0:03:13.77,0:03:15.56,Default,,0000,0000,0000,,distribution is a little\Nuneven in one
Dialogue: 0,0:03:15.56,0:03:16.53,Default,,0000,0000,0000,,neon atom or another.
Dialogue: 0,0:03:16.53,0:03:20.08,Default,,0000,0000,0000,,So if in this neon atom,\Ntemporarily its eight valence
Dialogue: 0,0:03:20.08,0:03:24.23,Default,,0000,0000,0000,,electrons just happen to be\Nlike, you know, one, two,
Dialogue: 0,0:03:24.23,0:03:28.71,Default,,0000,0000,0000,,three, four, five, six, seven,\Neight, then what does this
Dialogue: 0,0:03:28.71,0:03:29.54,Default,,0000,0000,0000,,neon atom look like?
Dialogue: 0,0:03:29.54,0:03:32.24,Default,,0000,0000,0000,,It temporarily has a\Nslight charge in
Dialogue: 0,0:03:32.24,0:03:33.12,Default,,0000,0000,0000,,this direction, right?
Dialogue: 0,0:03:33.12,0:03:36.77,Default,,0000,0000,0000,,It'll feel like this side is\Nmore negative than this side
Dialogue: 0,0:03:36.77,0:03:39.17,Default,,0000,0000,0000,,or this side is more positive\Nthan that side.
Dialogue: 0,0:03:39.17,0:03:45.00,Default,,0000,0000,0000,,Similarly, if at that very same\Nmoment I had another neon
Dialogue: 0,0:03:45.00,0:03:49.71,Default,,0000,0000,0000,,that had one, two, three, four,\Nfive, six, seven, eight,
Dialogue: 0,0:03:49.71,0:03:52.94,Default,,0000,0000,0000,,that had a similar-- actually,\Nlet me do that differently.
Dialogue: 0,0:03:52.94,0:03:56.65,Default,,0000,0000,0000,,Let's say that this neon atom is\Nlike this: one, two, three,
Dialogue: 0,0:03:56.65,0:04:00.93,Default,,0000,0000,0000,,four, five, six, seven, eight.
Dialogue: 0,0:04:00.93,0:04:04.62,Default,,0000,0000,0000,,So here, and I'll do it in a\Ndark color because it's a very
Dialogue: 0,0:04:04.62,0:04:05.33,Default,,0000,0000,0000,,faint force.
Dialogue: 0,0:04:05.33,0:04:06.50,Default,,0000,0000,0000,,So this would be a\Nlittle negative.
Dialogue: 0,0:04:06.50,0:04:10.06,Default,,0000,0000,0000,,Temporarly, just for that single\Nmoment in time, this
Dialogue: 0,0:04:10.06,0:04:11.13,Default,,0000,0000,0000,,will be kind of negative.
Dialogue: 0,0:04:11.13,0:04:12.40,Default,,0000,0000,0000,,That'll be positive.
Dialogue: 0,0:04:12.40,0:04:14.53,Default,,0000,0000,0000,,This side will be negative.
Dialogue: 0,0:04:14.53,0:04:16.02,Default,,0000,0000,0000,,This side will be positive.
Dialogue: 0,0:04:16.02,0:04:18.40,Default,,0000,0000,0000,,So you're going to have a little\Nbit of an attraction
Dialogue: 0,0:04:18.40,0:04:21.91,Default,,0000,0000,0000,,for that very small moment of\Ntime between this neon and
Dialogue: 0,0:04:21.91,0:04:23.34,Default,,0000,0000,0000,,this neon, and then it'll\Ndisappear, because the
Dialogue: 0,0:04:23.34,0:04:25.16,Default,,0000,0000,0000,,electrons will reconfigure.
Dialogue: 0,0:04:25.16,0:04:29.15,Default,,0000,0000,0000,,But the important thing to\Nrealize is that almost at no
Dialogue: 0,0:04:29.15,0:04:31.58,Default,,0000,0000,0000,,point is neon's electrons\Ngoing to be completely
Dialogue: 0,0:04:31.58,0:04:32.14,Default,,0000,0000,0000,,distributed.
Dialogue: 0,0:04:32.14,0:04:34.46,Default,,0000,0000,0000,,So as long as there's always\Ngoing to be this haphazard
Dialogue: 0,0:04:34.46,0:04:37.76,Default,,0000,0000,0000,,distribution, there's always\Ngoing to be a little bit of
Dialogue: 0,0:04:37.76,0:04:40.91,Default,,0000,0000,0000,,a-- I don't want to say polar\Nbehavior, because that's
Dialogue: 0,0:04:40.91,0:04:42.28,Default,,0000,0000,0000,,almost too strong of a word.
Dialogue: 0,0:04:42.28,0:04:45.36,Default,,0000,0000,0000,,But there will always be a\Nlittle bit of an extra charge
Dialogue: 0,0:04:45.36,0:04:47.85,Default,,0000,0000,0000,,on one side or the other side\Nof an atom, which will allow
Dialogue: 0,0:04:47.85,0:04:50.75,Default,,0000,0000,0000,,it to attract it to the opposite\Nside charges of other
Dialogue: 0,0:04:50.75,0:04:53.04,Default,,0000,0000,0000,,similarly imbalanced\Nmolecules.
Dialogue: 0,0:04:53.04,0:04:55.51,Default,,0000,0000,0000,,And this is a very, very,\Nvery weak force.
Dialogue: 0,0:04:55.51,0:04:59.04,Default,,0000,0000,0000,,It's called the London\Ndispersion force.
Dialogue: 0,0:04:59.04,0:05:01.50,Default,,0000,0000,0000,,I think the guy who came up with\Nthis, Fritz London, who
Dialogue: 0,0:05:01.50,0:05:05.12,Default,,0000,0000,0000,,was neither-- well, he\Nwas not British.
Dialogue: 0,0:05:05.12,0:05:06.47,Default,,0000,0000,0000,,I think he was German-American.
Dialogue: 0,0:05:06.47,0:05:12.92,Default,,0000,0000,0000,,London dispersion force, and\Nit's the weakest of the van
Dialogue: 0,0:05:12.92,0:05:14.18,Default,,0000,0000,0000,,der Waals forces.
Dialogue: 0,0:05:14.18,0:05:18.98,Default,,0000,0000,0000,,
Dialogue: 0,0:05:18.98,0:05:20.81,Default,,0000,0000,0000,,I'm sure I'm not pronouncing\Nit correctly.
Dialogue: 0,0:05:20.81,0:05:23.89,Default,,0000,0000,0000,,And the van der Waals forces\Nare the class of all of the
Dialogue: 0,0:05:23.89,0:05:26.49,Default,,0000,0000,0000,,intermolecular, and in\Nthis case, neon-- the
Dialogue: 0,0:05:26.49,0:05:27.67,Default,,0000,0000,0000,,molecule, is an atom .
Dialogue: 0,0:05:27.67,0:05:30.04,Default,,0000,0000,0000,,It's just a one-atom molecule,\NI guess you could say.
Dialogue: 0,0:05:30.04,0:05:32.76,Default,,0000,0000,0000,,The van der Waals forces are\Nthe class of all of the
Dialogue: 0,0:05:32.76,0:05:36.01,Default,,0000,0000,0000,,intermolecular forces that are\Nnot covalent bonds and that
Dialogue: 0,0:05:36.01,0:05:38.65,Default,,0000,0000,0000,,aren't ionic bonds like we have\Nin salts, and we'll touch
Dialogue: 0,0:05:38.65,0:05:39.23,Default,,0000,0000,0000,,on those in a second.
Dialogue: 0,0:05:39.23,0:05:42.26,Default,,0000,0000,0000,,And the weakest of them are the\NLondon dispersion forces.
Dialogue: 0,0:05:42.26,0:05:45.29,Default,,0000,0000,0000,,So neon, these noble gases,\Nactually, all of these noble
Dialogue: 0,0:05:45.29,0:05:48.80,Default,,0000,0000,0000,,gases right here, the only thing\Nthat they experience are
Dialogue: 0,0:05:48.80,0:05:51.94,Default,,0000,0000,0000,,London dispersion forces, which\Nare the weakest of all
Dialogue: 0,0:05:51.94,0:05:53.92,Default,,0000,0000,0000,,of the intermolecular forces.
Dialogue: 0,0:05:53.92,0:05:57.19,Default,,0000,0000,0000,,And because of that, it takes\Nvery little energy to get them
Dialogue: 0,0:05:57.19,0:05:59.46,Default,,0000,0000,0000,,into a gaseous state.
Dialogue: 0,0:05:59.46,0:06:05.52,Default,,0000,0000,0000,,So at a very, very low\Ntemperature, the noble gases
Dialogue: 0,0:06:05.52,0:06:07.14,Default,,0000,0000,0000,,will turn into the\Ngaseous state.
Dialogue: 0,0:06:07.14,0:06:09.67,Default,,0000,0000,0000,,That's why they're called noble\Ngases, first of all.
Dialogue: 0,0:06:09.67,0:06:13.92,Default,,0000,0000,0000,,And they're the most likely\Nto behave like ideal gases
Dialogue: 0,0:06:13.92,0:06:15.82,Default,,0000,0000,0000,,because they have\Nvery, very small
Dialogue: 0,0:06:15.82,0:06:17.55,Default,,0000,0000,0000,,attraction to each other.
Dialogue: 0,0:06:17.55,0:06:18.50,Default,,0000,0000,0000,,Fair enough.
Dialogue: 0,0:06:18.50,0:06:20.88,Default,,0000,0000,0000,,Now, what happens when we go\Nto situations when we go to
Dialogue: 0,0:06:20.88,0:06:24.23,Default,,0000,0000,0000,,molecules that have better\Nattractions or that are a
Dialogue: 0,0:06:24.23,0:06:25.29,Default,,0000,0000,0000,,little bit more polar?
Dialogue: 0,0:06:25.29,0:06:27.67,Default,,0000,0000,0000,,Let's say I had hydrogen\Nchloride, right?
Dialogue: 0,0:06:27.67,0:06:30.48,Default,,0000,0000,0000,,Hydrogen, it's a little bit\Nambivalent about whether or
Dialogue: 0,0:06:30.48,0:06:31.66,Default,,0000,0000,0000,,not it keeps its electrons.
Dialogue: 0,0:06:31.66,0:06:35.18,Default,,0000,0000,0000,,Chloride wants to keep\Nthe electrons.
Dialogue: 0,0:06:35.18,0:06:37.25,Default,,0000,0000,0000,,Chloride's quite\Nelectronegative.
Dialogue: 0,0:06:37.25,0:06:39.59,Default,,0000,0000,0000,,It's less electronegative than\Nthese guys right here.
Dialogue: 0,0:06:39.59,0:06:42.71,Default,,0000,0000,0000,,These are kind of the\Nsuper-duper electron hogs,
Dialogue: 0,0:06:42.71,0:06:46.34,Default,,0000,0000,0000,,nitrogen, oxygen, and fluorine,\Nbut chlorine is
Dialogue: 0,0:06:46.34,0:06:47.65,Default,,0000,0000,0000,,pretty electronegative.
Dialogue: 0,0:06:47.65,0:06:50.94,Default,,0000,0000,0000,,So if I have hydrogen chloride,\Nso I have the
Dialogue: 0,0:06:50.94,0:06:57.20,Default,,0000,0000,0000,,chlorine atom right here, it has\Nseven electrons and then
Dialogue: 0,0:06:57.20,0:07:00.21,Default,,0000,0000,0000,,it shares an electron\Nwith the hydrogen.
Dialogue: 0,0:07:00.21,0:07:02.08,Default,,0000,0000,0000,,It shares an electron with\Nthe hydrogen, and I'll
Dialogue: 0,0:07:02.08,0:07:03.41,Default,,0000,0000,0000,,just do it like that.
Dialogue: 0,0:07:03.41,0:07:05.71,Default,,0000,0000,0000,,Because this is a good bit\Nmore electronegative than
Dialogue: 0,0:07:05.71,0:07:09.32,Default,,0000,0000,0000,,hydrogen, the electrons spend\Na lot of time out here.
Dialogue: 0,0:07:09.32,0:07:12.95,Default,,0000,0000,0000,,So what you end up having is a\Npartial negative charge on the
Dialogue: 0,0:07:12.95,0:07:14.74,Default,,0000,0000,0000,,side, where the electron\Nhog is, and a
Dialogue: 0,0:07:14.74,0:07:17.27,Default,,0000,0000,0000,,partial positive side.
Dialogue: 0,0:07:17.27,0:07:18.86,Default,,0000,0000,0000,,And this is actually\Nvery analogous to
Dialogue: 0,0:07:18.86,0:07:19.87,Default,,0000,0000,0000,,the hydrogen bonds.
Dialogue: 0,0:07:19.87,0:07:22.71,Default,,0000,0000,0000,,Hydrogen bonds are actually a\Nclass of this type of bond,
Dialogue: 0,0:07:22.71,0:07:25.94,Default,,0000,0000,0000,,which is called a dipole bond,\Nor dipole-dipole interaction.
Dialogue: 0,0:07:25.94,0:07:28.67,Default,,0000,0000,0000,,So if I have one chlorine atom\Nlike that and if I have
Dialogue: 0,0:07:28.67,0:07:31.70,Default,,0000,0000,0000,,another chlorine atom,\Nthe other chlorine
Dialogue: 0,0:07:31.70,0:07:33.73,Default,,0000,0000,0000,,atoms looks like this.
Dialogue: 0,0:07:33.73,0:07:37.48,Default,,0000,0000,0000,,If I have the other chlorine\Natom-- let me copy and paste
Dialogue: 0,0:07:37.48,0:07:41.65,Default,,0000,0000,0000,,it-- right there, then\Nyou'll have this
Dialogue: 0,0:07:41.65,0:07:44.32,Default,,0000,0000,0000,,attraction between them.
Dialogue: 0,0:07:44.32,0:07:47.44,Default,,0000,0000,0000,,You'll have this attraction\Nbetween these two chlorine
Dialogue: 0,0:07:47.44,0:07:49.49,Default,,0000,0000,0000,,atoms-- oh, sorry,\Nbetween these two
Dialogue: 0,0:07:49.49,0:07:51.93,Default,,0000,0000,0000,,hydrogen chloride molecules.
Dialogue: 0,0:07:51.93,0:07:57.12,Default,,0000,0000,0000,,And the positive side, the\Npositive pole of this dipole
Dialogue: 0,0:07:57.12,0:07:59.41,Default,,0000,0000,0000,,is the hydrogen side, because\Nthe electrons have kind of
Dialogue: 0,0:07:59.41,0:08:02.60,Default,,0000,0000,0000,,left it, will be attracted\Nto the chlorine side
Dialogue: 0,0:08:02.60,0:08:04.03,Default,,0000,0000,0000,,of the other molecules.
Dialogue: 0,0:08:04.03,0:08:07.59,Default,,0000,0000,0000,,And because this van der Waals\Nforce, this dipole-dipole
Dialogue: 0,0:08:07.59,0:08:11.79,Default,,0000,0000,0000,,interaction is stronger than\Na London dispersion force.
Dialogue: 0,0:08:11.79,0:08:14.54,Default,,0000,0000,0000,,And just to be clear, London\Ndispersion forces occur in all
Dialogue: 0,0:08:14.54,0:08:15.96,Default,,0000,0000,0000,,molecular interactions.
Dialogue: 0,0:08:15.96,0:08:18.63,Default,,0000,0000,0000,,It's just that it's very weak\Nwhen you compare it to pretty
Dialogue: 0,0:08:18.63,0:08:19.57,Default,,0000,0000,0000,,much anything else.
Dialogue: 0,0:08:19.57,0:08:22.81,Default,,0000,0000,0000,,It only becomes relevant when\Nyou talk about things with
Dialogue: 0,0:08:22.81,0:08:23.81,Default,,0000,0000,0000,,noble gases.
Dialogue: 0,0:08:23.81,0:08:26.96,Default,,0000,0000,0000,,Even here, they're also London\Ndispersion forces when the
Dialogue: 0,0:08:26.96,0:08:29.36,Default,,0000,0000,0000,,electron distribution just\Nhappens to go one way or the
Dialogue: 0,0:08:29.36,0:08:31.39,Default,,0000,0000,0000,,other for a single\Ninstant of time.
Dialogue: 0,0:08:31.39,0:08:34.19,Default,,0000,0000,0000,,But this dipole-dipole\Ninteraction is much stronger.
Dialogue: 0,0:08:34.19,0:08:38.13,Default,,0000,0000,0000,,And because it's much stronger,\Nhydrogen chloride is
Dialogue: 0,0:08:38.13,0:08:40.70,Default,,0000,0000,0000,,going to take more energy to,\None, get into the liquid
Dialogue: 0,0:08:40.70,0:08:44.45,Default,,0000,0000,0000,,state, or even more, get into\Nthe gaseous state than, say,
Dialogue: 0,0:08:44.45,0:08:47.53,Default,,0000,0000,0000,,just a sample of helium gas.
Dialogue: 0,0:08:47.53,0:08:49.70,Default,,0000,0000,0000,,Now, when you get even more\Nelectronegative, when this
Dialogue: 0,0:08:49.70,0:08:51.22,Default,,0000,0000,0000,,guy's even more electronegative\Nwhen you're
Dialogue: 0,0:08:51.22,0:08:54.92,Default,,0000,0000,0000,,dealing with nitrogen, oxygen\Nor fluorine, you get into a
Dialogue: 0,0:08:54.92,0:08:58.72,Default,,0000,0000,0000,,special case of dipole-dipole\Ninteractions, and that's the
Dialogue: 0,0:08:58.72,0:09:00.59,Default,,0000,0000,0000,,hydrogen bond.
Dialogue: 0,0:09:00.59,0:09:06.48,Default,,0000,0000,0000,,So it's really the same thing if\Nyou have hydrogen fluoride,
Dialogue: 0,0:09:06.48,0:09:12.14,Default,,0000,0000,0000,,a bunch of hydrogen fluorides\Naround the place.
Dialogue: 0,0:09:12.14,0:09:16.18,Default,,0000,0000,0000,,Maybe I could write fluoride,\Nand I'll write hydrogen
Dialogue: 0,0:09:16.18,0:09:17.10,Default,,0000,0000,0000,,fluoride here.
Dialogue: 0,0:09:17.10,0:09:19.03,Default,,0000,0000,0000,,Fluoride its\Nultra-electronegative.
Dialogue: 0,0:09:19.03,0:09:23.22,Default,,0000,0000,0000,,It's one of the three most\Nelectronegative atoms on the
Dialogue: 0,0:09:23.22,0:09:27.95,Default,,0000,0000,0000,,Periodic Table, and\Nso it pretty much
Dialogue: 0,0:09:27.95,0:09:30.29,Default,,0000,0000,0000,,hogs all of the electrons.
Dialogue: 0,0:09:30.29,0:09:35.08,Default,,0000,0000,0000,,So this is a super-strong case\Nof the dipole-dipole
Dialogue: 0,0:09:35.08,0:09:37.92,Default,,0000,0000,0000,,interaction, where here, all of\Nthe electrons are going to
Dialogue: 0,0:09:37.92,0:09:40.11,Default,,0000,0000,0000,,be hogged around the\Nfluorine side.
Dialogue: 0,0:09:40.11,0:09:42.18,Default,,0000,0000,0000,,So you're going to have a\Npartial positive charge,
Dialogue: 0,0:09:42.18,0:09:46.27,Default,,0000,0000,0000,,partial negative side, partial\Npositive, partial negative,
Dialogue: 0,0:09:46.27,0:09:49.10,Default,,0000,0000,0000,,partial positive, partial\Nnegative and so on.
Dialogue: 0,0:09:49.10,0:09:52.83,Default,,0000,0000,0000,,So you're going to have this,\Nwhich is really a dipole
Dialogue: 0,0:09:52.83,0:09:53.43,Default,,0000,0000,0000,,interaction.
Dialogue: 0,0:09:53.43,0:09:55.99,Default,,0000,0000,0000,,But it's a very strong dipole\Ninteraction, so people call it
Dialogue: 0,0:09:55.99,0:09:59.47,Default,,0000,0000,0000,,a hydrogen bond because it's\Ndealing with hydrogen and a
Dialogue: 0,0:09:59.47,0:10:02.64,Default,,0000,0000,0000,,very electronegative atom, where\Nthe electronegative atom
Dialogue: 0,0:10:02.64,0:10:05.69,Default,,0000,0000,0000,,is pretty much hogging all of\Nhydrogen's one electron.
Dialogue: 0,0:10:05.69,0:10:07.72,Default,,0000,0000,0000,,So hydrogen is sitting out here\Nwith just a proton, so
Dialogue: 0,0:10:07.72,0:10:09.56,Default,,0000,0000,0000,,it's going to be pretty\Npositive, and it's really
Dialogue: 0,0:10:09.56,0:10:12.66,Default,,0000,0000,0000,,attracted to the negative\Nside of these molecules.
Dialogue: 0,0:10:12.66,0:10:16.53,Default,,0000,0000,0000,,But hydrogen, all of these\Nare van der Waals.
Dialogue: 0,0:10:16.53,0:10:19.70,Default,,0000,0000,0000,,So van der Waals, the weakest\Nis London dispersion.
Dialogue: 0,0:10:19.70,0:10:24.61,Default,,0000,0000,0000,,Then if you have a molecule with\Na more electronegative
Dialogue: 0,0:10:24.61,0:10:27.90,Default,,0000,0000,0000,,atom, then you start having a\Ndipole, where you have one
Dialogue: 0,0:10:27.90,0:10:31.33,Default,,0000,0000,0000,,side where molecule becomes\Npolar and you have the
Dialogue: 0,0:10:31.33,0:10:33.29,Default,,0000,0000,0000,,interaction between the positive\Nand the negative side
Dialogue: 0,0:10:33.29,0:10:33.67,Default,,0000,0000,0000,,of the pole.
Dialogue: 0,0:10:33.67,0:10:36.02,Default,,0000,0000,0000,,It gets a dipole-dipole\Ninteraction.
Dialogue: 0,0:10:36.02,0:10:39.39,Default,,0000,0000,0000,,And then an even stronger type\Nof bond is a hydrogen bond
Dialogue: 0,0:10:39.39,0:10:41.78,Default,,0000,0000,0000,,because the\Nsuper-electronegative atom is
Dialogue: 0,0:10:41.78,0:10:44.67,Default,,0000,0000,0000,,essentially stripping off the\Nelectron of the hydrogen, or
Dialogue: 0,0:10:44.67,0:10:46.06,Default,,0000,0000,0000,,almost stripping it off.
Dialogue: 0,0:10:46.06,0:10:47.25,Default,,0000,0000,0000,,It's still shared,\Nbut it's all on
Dialogue: 0,0:10:47.25,0:10:49.42,Default,,0000,0000,0000,,that side of the molecule.
Dialogue: 0,0:10:49.42,0:10:51.94,Default,,0000,0000,0000,,Since this is even a stronger\Nbond between molecules, it
Dialogue: 0,0:10:51.94,0:10:53.66,Default,,0000,0000,0000,,will have even a higher\Nboiling point.
Dialogue: 0,0:10:53.66,0:11:01.38,Default,,0000,0000,0000,,So London dispersion, and you\Nhave dipole or polar bonds,
Dialogue: 0,0:11:01.38,0:11:06.37,Default,,0000,0000,0000,,and then you have\Nhydrogen bonds.
Dialogue: 0,0:11:06.37,0:11:09.31,Default,,0000,0000,0000,,All of these are van der\NWaals, but because the
Dialogue: 0,0:11:09.31,0:11:13.36,Default,,0000,0000,0000,,strength of the intermolecular\Nbond gets stronger, boiling
Dialogue: 0,0:11:13.36,0:11:18.30,Default,,0000,0000,0000,,point goes up because it takes\Nmore and more energy to
Dialogue: 0,0:11:18.30,0:11:21.39,Default,,0000,0000,0000,,separate these from\Neach other.
Dialogue: 0,0:11:21.39,0:11:23.19,Default,,0000,0000,0000,,In the next video-- I realize\NI'm out of time.
Dialogue: 0,0:11:23.19,0:11:26.04,Default,,0000,0000,0000,,So this is a good survey, I\Nthink, of just the different
Dialogue: 0,0:11:26.04,0:11:28.37,Default,,0000,0000,0000,,types of intermolecular\Ninteractions that aren't
Dialogue: 0,0:11:28.37,0:11:29.95,Default,,0000,0000,0000,,necessarily covalent or ionic.
Dialogue: 0,0:11:29.95,0:11:32.36,Default,,0000,0000,0000,,In the next video, I'll talk\Nabout some of the covalent and
Dialogue: 0,0:11:32.36,0:11:35.90,Default,,0000,0000,0000,,ionic types of structures that\Ncan be formed and how that
Dialogue: 0,0:11:35.90,0:11:38.90,Default,,0000,0000,0000,,might affect the different\Nboiling points.