[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.61,0:00:01.35,Default,,0000,0000,0000,,If you're wondering
Dialogue: 0,0:00:01.35,0:00:08.35,Default,,0000,0000,0000,,this is how the most revolutionary course\Nin biology of all time begins.
Dialogue: 0,0:00:08.38,0:00:12.17,Default,,0000,0000,0000,,Come today to learn about covalent and ionic\Nand hydrogen bonds
Dialogue: 0,0:00:12.17,0:00:13.58,Default,,0000,0000,0000,,What about electron orbitals
Dialogue: 0,0:00:13.58,0:00:14.70,Default,,0000,0000,0000,,and the octet rule
Dialogue: 0,0:00:14.70,0:00:18.07,Default,,0000,0000,0000,,and what does it all have to do with a mad\Nman named Gilbert Lewis?
Dialogue: 0,0:00:18.07,0:00:23.17,Default,,0000,0000,0000,,It's all contained within.
Dialogue: 0,0:00:23.17,0:00:30.17,Default,,0000,0000,0000,,Hello, I’m Hank
Dialogue: 0,0:00:31.79,0:00:33.97,Default,,0000,0000,0000,,I assume you’re here because you’re interested\Nin biology
Dialogue: 0,0:00:33.97,0:00:37.37,Default,,0000,0000,0000,,and if you are, that makes sense because
Dialogue: 0,0:00:37.37,0:00:42.60,Default,,0000,0000,0000,,like any good 50 Cent song, biology is just\Nabout sex and not dying.
Dialogue: 0,0:00:42.60,0:00:45.96,Default,,0000,0000,0000,,Everyone watching this should be interested\Nin sex and not dying
Dialogue: 0,0:00:45.96,0:00:49.15,Default,,0000,0000,0000,,being that you are, I assume, a human being.
Dialogue: 0,0:00:49.15,0:00:52.80,Default,,0000,0000,0000,,I'm going to be teaching this biology course\Ndifferently than most courses you've ever
Dialogue: 0,0:00:52.80,0:00:53.50,Default,,0000,0000,0000,,taken in your life
Dialogue: 0,0:00:53.50,0:00:57.13,Default,,0000,0000,0000,,For example, I'm not going to spend the first\Nclass
Dialogue: 0,0:00:57.13,0:00:59.74,Default,,0000,0000,0000,,talking about how I’m going to spend the\Nrest of class.
Dialogue: 0,0:00:59.74,0:01:02.86,Default,,0000,0000,0000,,I'm just going to start teaching you, like\Nright about now.
Dialogue: 0,0:01:02.86,0:01:04.89,Default,,0000,0000,0000,,I may say one more thing before I start teaching.
Dialogue: 0,0:01:04.89,0:01:06.69,Default,,0000,0000,0000,,Yes, I am going to!
Dialogue: 0,0:01:06.69,0:01:10.72,Default,,0000,0000,0000,,It's that: if I’m going too fast for you,\Nthe great thing about YouTube is
Dialogue: 0,0:01:10.72,0:01:12.77,Default,,0000,0000,0000,,that you can just rewind.
Dialogue: 0,0:01:12.77,0:01:14.53,Default,,0000,0000,0000,,Watch stuff over and over again if it's confusing.
Dialogue: 0,0:01:14.53,0:01:17.14,Default,,0000,0000,0000,,Hopefully, it will become less confusing.
Dialogue: 0,0:01:17.14,0:01:20.36,Default,,0000,0000,0000,,And you're even allowed to fast forward through\Nthe bits that you already know.
Dialogue: 0,0:01:20.36,0:01:23.78,Default,,0000,0000,0000,,Another tip, you can actually even use the\Nnumber keys on your keyboard to move around
Dialogue: 0,0:01:23.78,0:01:24.65,Default,,0000,0000,0000,,in the video.
Dialogue: 0,0:01:24.65,0:01:28.87,Default,,0000,0000,0000,,And I promise, you can do this to me as much\Nas you want and I'm totally not going to mind.
Dialogue: 0,0:01:28.87,0:01:31.84,Default,,0000,0000,0000,,A great professor of mine once told me that\Nin order to really understand any topic
Dialogue: 0,0:01:31.84,0:01:36.28,Default,,0000,0000,0000,,you have to understand a little bit of the\Nlevel of complexity just below that topic.
Dialogue: 0,0:01:36.28,0:01:39.29,Default,,0000,0000,0000,,The level of complexity just below biology\Nis chemistry
Dialogue: 0,0:01:39.29,0:01:43.64,Default,,0000,0000,0000,,unless you're a biochemist in which case you\Nwould argue that it's biochemistry.
Dialogue: 0,0:01:43.64,0:01:48.99,Default,,0000,0000,0000,,Either way, we're gonna have to know a little\Nbit of chemistry in order to get through biology.
Dialogue: 0,0:01:48.99,0:01:51.92,Default,,0000,0000,0000,,And so THAT, my friends, is where we're going\Nto start.
Dialogue: 0,0:01:51.92,0:01:56.04,Default,,0000,0000,0000,,I am a collection of organic molecules called\NHank Green.
Dialogue: 0,0:01:56.04,0:01:59.23,Default,,0000,0000,0000,,Organic compounds are a class of compounds\Nthat contain carbon.
Dialogue: 0,0:01:59.23,0:02:04.15,Default,,0000,0000,0000,,And carbon is this sexy little minx on the\Nperiodic table
Dialogue: 0,0:02:04.15,0:02:06.48,Default,,0000,0000,0000,,that's, you know...
Dialogue: 0,0:02:06.48,0:02:08.12,Default,,0000,0000,0000,,disinterested in monogamy.
Dialogue: 0,0:02:08.12,0:02:09.49,Default,,0000,0000,0000,,A jezebel. Bit of a tramp. Hussy.
Dialogue: 0,0:02:09.49,0:02:11.92,Default,,0000,0000,0000,,When I say carbon is small I mean that it's\Nactually
Dialogue: 0,0:02:11.92,0:02:14.50,Default,,0000,0000,0000,,as an atom, it's a relatively small atom.
Dialogue: 0,0:02:14.50,0:02:18.57,Default,,0000,0000,0000,,It has 6 protons and 6 neutrons for a total\Natomic weight of 12.
Dialogue: 0,0:02:18.57,0:02:20.25,Default,,0000,0000,0000,,Because of that, carbon doesn't take up a\Nlot of space.
Dialogue: 0,0:02:20.25,0:02:25.76,Default,,0000,0000,0000,,And so carbon can form itself into weird rings,\Nand sheets and spirals
Dialogue: 0,0:02:25.76,0:02:27.60,Default,,0000,0000,0000,,and double and even triple bonds.
Dialogue: 0,0:02:27.60,0:02:32.79,Default,,0000,0000,0000,,It can do all sorts of things that could never\Nbe accomplished by more bulky atoms.
Dialogue: 0,0:02:32.79,0:02:37.73,Default,,0000,0000,0000,,It's basically, your atomic equivalent of\Nan olympic gymnast.
Dialogue: 0,0:02:37.73,0:02:42.34,Default,,0000,0000,0000,,It can only do all of those wonderful, beautiful,\Nelegant things because it's kind of tiny.
Dialogue: 0,0:02:42.34,0:02:44.47,Default,,0000,0000,0000,,It's also said that carbon is kind
Dialogue: 0,0:02:44.47,0:02:48.16,Default,,0000,0000,0000,,and that's an interesting sort of thing to\Nsay about an atom.
Dialogue: 0,0:02:48.16,0:02:49.56,Default,,0000,0000,0000,,It's not like some other elements that are\Njust
Dialogue: 0,0:02:49.56,0:02:52.02,Default,,0000,0000,0000,,desperately trying to do anything they can
Dialogue: 0,0:02:52.02,0:02:53.59,Default,,0000,0000,0000,,to fill up their electron orbitals.
Dialogue: 0,0:02:53.59,0:02:56.62,Default,,0000,0000,0000,,No, carbon knows what it's like to be alone,\Nand so it's not all
Dialogue: 0,0:02:56.62,0:02:59.30,Default,,0000,0000,0000,,“Please! I'll do anything for your electrons!”
Dialogue: 0,0:02:59.30,0:03:02.34,Default,,0000,0000,0000,,needy like fluorine or chlorine or sodium\Nis.
Dialogue: 0,0:03:02.34,0:03:05.05,Default,,0000,0000,0000,,Elements like chlorine if you breath them\Nin they like literally tear up your insides
Dialogue: 0,0:03:05.05,0:03:10.15,Default,,0000,0000,0000,,and sodium, sodium is insane if you put it\Nin water it explodes!
Dialogue: 0,0:03:10.15,0:03:10.95,Default,,0000,0000,0000,,Carbon though...
Dialogue: 0,0:03:10.95,0:03:11.66,Default,,0000,0000,0000,,Meh.
Dialogue: 0,0:03:11.66,0:03:15.61,Default,,0000,0000,0000,,It wants more electrons, but it's not gonna\Nkill to get them.
Dialogue: 0,0:03:15.61,0:03:18.57,Default,,0000,0000,0000,,It makes and breaks bonds like a 13-year old\Nmall rat.
Dialogue: 0,0:03:18.57,0:03:20.22,Default,,0000,0000,0000,,And it doesn't even hold a grudge.
Dialogue: 0,0:03:20.22,0:03:26.08,Default,,0000,0000,0000,,Carbon is also, as I mentioned before, a bit\Nof a tramp, because, it needs four extra electrons
Dialogue: 0,0:03:26.08,0:03:28.79,Default,,0000,0000,0000,,and so it'll bond with pretty much whoever\Nhappens to be nearby
Dialogue: 0,0:03:28.79,0:03:32.68,Default,,0000,0000,0000,,And also because it needs four electrons,\Nit'll bond with two, or three
Dialogue: 0,0:03:32.68,0:03:35.45,Default,,0000,0000,0000,,or even four of those things at the same time
Dialogue: 0,0:03:35.45,0:03:39.86,Default,,0000,0000,0000,,And carbon is willing and interested to bond\Nwith lots of different molecules
Dialogue: 0,0:03:39.86,0:03:42.06,Default,,0000,0000,0000,,like hydrogen, oxygen, phosphorous, nitrogen
Dialogue: 0,0:03:42.06,0:03:43.94,Default,,0000,0000,0000,,or to other molecules of carbon.
Dialogue: 0,0:03:43.94,0:03:46.23,Default,,0000,0000,0000,,It can do this in infinite configurations
Dialogue: 0,0:03:46.23,0:03:52.18,Default,,0000,0000,0000,,allowing it to be the core atom of complicated\Nstructures that make living things like ourselves
Dialogue: 0,0:03:52.18,0:03:57.90,Default,,0000,0000,0000,,because carbon is this perfect mix of small,\Nkind, and a little bit trampy
Dialogue: 0,0:03:57.90,0:04:00.39,Default,,0000,0000,0000,,life is entirely based on this element.
Dialogue: 0,0:04:00.39,0:04:02.93,Default,,0000,0000,0000,,Carbon is the foundation of biology.
Dialogue: 0,0:04:02.93,0:04:07.35,Default,,0000,0000,0000,,It's so fundamental that scientists have a\Npretty difficult time
Dialogue: 0,0:04:07.35,0:04:10.75,Default,,0000,0000,0000,,even conceiving of life that isn't based on\Ncarbon.
Dialogue: 0,0:04:10.75,0:04:15.16,Default,,0000,0000,0000,,Life is only possible on earth because carbon\Nis always floating around in our atmosphere
Dialogue: 0,0:04:15.16,0:04:16.71,Default,,0000,0000,0000,,in the form of carbon dioxide.
Dialogue: 0,0:04:16.71,0:04:19.77,Default,,0000,0000,0000,,So it's important to note, when I talk about\Ncarbon bonding with other elements
Dialogue: 0,0:04:19.77,0:04:23.17,Default,,0000,0000,0000,,I'm not actually talking about sex, it's just\Na useful analogy.
Dialogue: 0,0:04:23.17,0:04:29.08,Default,,0000,0000,0000,,Carbon, on it's own, is an atom with 6 protons,\N6 neutrons, and 6 electrons.
Dialogue: 0,0:04:29.08,0:04:32.85,Default,,0000,0000,0000,,Atoms, have electron shells, and they need\Nto have these shells filled
Dialogue: 0,0:04:32.85,0:04:35.10,Default,,0000,0000,0000,,in order to be happy, fulfilled atoms.
Dialogue: 0,0:04:35.10,0:04:37.78,Default,,0000,0000,0000,,So carbon, has 6 total electrons, 2 for the\Nfirst shell
Dialogue: 0,0:04:37.78,0:04:38.73,Default,,0000,0000,0000,,so it's totally happy
Dialogue: 0,0:04:38.73,0:04:41.65,Default,,0000,0000,0000,,and 4 of the 8 it needs to fill the second\Nshell.
Dialogue: 0,0:04:41.65,0:04:43.42,Default,,0000,0000,0000,,Carbon forms a type of bond that we call covalent.
Dialogue: 0,0:04:43.42,0:04:46.37,Default,,0000,0000,0000,,This is when atoms actually are sharing electrons\Nwith each other.
Dialogue: 0,0:04:46.37,0:04:51.02,Default,,0000,0000,0000,,So in the case of methane, which is pretty\Nmuch the simplest carbon compound ever.
Dialogue: 0,0:04:51.02,0:04:55.08,Default,,0000,0000,0000,,Carbon is sharing it's 4 electrons, in it's\Nouter electron shell, with 4 atoms of hydrogen.
Dialogue: 0,0:04:55.08,0:04:59.19,Default,,0000,0000,0000,,Hydrogen atoms only have 1 electron, so they\Nwant their first S orbital filled.
Dialogue: 0,0:04:59.19,0:05:01.76,Default,,0000,0000,0000,,Carbon shares its 4 electrons with those 4\Nhydrogens
Dialogue: 0,0:05:01.76,0:05:04.60,Default,,0000,0000,0000,,and those 4 hydrogens each share 1 electron\Nwith carbon.
Dialogue: 0,0:05:04.60,0:05:05.49,Default,,0000,0000,0000,,So everybody's happy.
Dialogue: 0,0:05:05.49,0:05:10.59,Default,,0000,0000,0000,,In chemistry and biology this is often represented\Nby what we call Lewis dot structures.
Dialogue: 0,0:05:10.59,0:05:16.65,Default,,0000,0000,0000,,Good lord, I'm in a chair!
Dialogue: 0,0:05:16.65,0:05:19.49,Default,,0000,0000,0000,,I'm in a chair and there's a book.
Dialogue: 0,0:05:19.49,0:05:21.95,Default,,0000,0000,0000,,Apparently I have something to tell you that's\Nin this book.
Dialogue: 0,0:05:21.95,0:05:25.87,Default,,0000,0000,0000,,Which is a book called Lewis: Acids and Bases.
Dialogue: 0,0:05:25.87,0:05:27.18,Default,,0000,0000,0000,,By Hank Green
Dialogue: 0,0:05:27.18,0:05:30.23,Default,,0000,0000,0000,,Gilbert Lewis, the guy who thought up Lewis\Ndot structures
Dialogue: 0,0:05:30.23,0:05:33.01,Default,,0000,0000,0000,,was also the guy behind Lewis Acids and Bases
Dialogue: 0,0:05:33.01,0:05:35.13,Default,,0000,0000,0000,,and he was nominated for the nobel prize
Dialogue: 0,0:05:35.13,0:05:37.45,Default,,0000,0000,0000,,35 times.
Dialogue: 0,0:05:37.45,0:05:40.30,Default,,0000,0000,0000,,This is more nominations than anyone else\Never in history.
Dialogue: 0,0:05:40.30,0:05:43.56,Default,,0000,0000,0000,,And the number of times he won was roughly\Nthe same number of times
Dialogue: 0,0:05:43.56,0:05:45.94,Default,,0000,0000,0000,,that everyone else in the world has won.
Dialogue: 0,0:05:45.94,0:05:46.63,Default,,0000,0000,0000,,Which is zero.
Dialogue: 0,0:05:46.63,0:05:48.77,Default,,0000,0000,0000,,Lewis disliked this a great deal.
Dialogue: 0,0:05:48.77,0:05:52.64,Default,,0000,0000,0000,,It's kind of like a baseball player having\Nmore hits than any other player in history
Dialogue: 0,0:05:52.64,0:05:53.46,Default,,0000,0000,0000,,and no home runs.
Dialogue: 0,0:05:53.46,0:05:56.19,Default,,0000,0000,0000,,He may have been the most influential chemist\Nof all time.
Dialogue: 0,0:05:56.19,0:06:00.05,Default,,0000,0000,0000,,He coined the term photon, he revolutionized\Nhow we think about acids and bases
Dialogue: 0,0:06:00.05,0:06:02.31,Default,,0000,0000,0000,,and he produced the first molecule of heavy\Nwater.
Dialogue: 0,0:06:02.31,0:06:06.41,Default,,0000,0000,0000,,He was the first person to conceptualize the\Ncovalent bond that we're talking about right
Dialogue: 0,0:06:06.41,0:06:06.66,Default,,0000,0000,0000,,now.
Dialogue: 0,0:06:06.50,0:06:10.82,Default,,0000,0000,0000,,Gilbert Lewis died alone in his laboratory\Nwhile working on cyanide compounds
Dialogue: 0,0:06:10.82,0:06:14.03,Default,,0000,0000,0000,,after having had lunch with a younger, more\Ncharismatic colleague
Dialogue: 0,0:06:14.03,0:06:17.87,Default,,0000,0000,0000,,who had won the Nobel Prize and who had worked\Non the Manhattan project.
Dialogue: 0,0:06:17.87,0:06:21.13,Default,,0000,0000,0000,,Many suspect that he killed himself with the\Ncyanide compounds he was working on
Dialogue: 0,0:06:21.13,0:06:25.03,Default,,0000,0000,0000,,but the medical examiner said heart attack,\Nwithout really looking into it.
Dialogue: 0,0:06:25.03,0:06:27.72,Default,,0000,0000,0000,,I told you all of that because
Dialogue: 0,0:06:27.72,0:06:34.70,Default,,0000,0000,0000,,the little Lewis dot structure that we use\Nto represent how atoms bond to each other
Dialogue: 0,0:06:34.70,0:06:40.46,Default,,0000,0000,0000,,is something that was created by a troubled\Nmad genius.
Dialogue: 0,0:06:40.46,0:06:43.99,Default,,0000,0000,0000,,It's not some abstract scientific thing that's\Nalways existed.
Dialogue: 0,0:06:43.99,0:06:45.83,Default,,0000,0000,0000,,It's a tool that was thought up by a guy
Dialogue: 0,0:06:45.83,0:06:48.57,Default,,0000,0000,0000,,and it was so useful that we've been using\Nit ever since.
Dialogue: 0,0:06:48.57,0:06:52.18,Default,,0000,0000,0000,,In biology most compounds can be displayed\Nin Lewis dot structure form
Dialogue: 0,0:06:52.18,0:06:52.100,Default,,0000,0000,0000,,and here's how that works:
Dialogue: 0,0:06:52.100,0:06:56.87,Default,,0000,0000,0000,,These structures basically show how atoms\Nbond together to make up molecules.
Dialogue: 0,0:06:56.87,0:06:59.05,Default,,0000,0000,0000,,And one of the rules of thumb when you're\Nmaking these diagrams
Dialogue: 0,0:06:59.05,0:07:02.29,Default,,0000,0000,0000,,is that the elements that we're working with\Nhere react with one another in such a way
Dialogue: 0,0:07:02.29,0:07:05.47,Default,,0000,0000,0000,,that each atom ends up with 8 electrons in\Nit's outermost shell.
Dialogue: 0,0:07:05.47,0:07:07.18,Default,,0000,0000,0000,,That is called the Octet Rule.
Dialogue: 0,0:07:07.18,0:07:11.63,Default,,0000,0000,0000,,Because atoms want to complete their octets\Nof electrons to be happy and satisfied.
Dialogue: 0,0:07:11.63,0:07:15.32,Default,,0000,0000,0000,,Oxygen has 6 electrons in it's octet and needs\N2 which is why we get H2O
Dialogue: 0,0:07:15.32,0:07:16.81,Default,,0000,0000,0000,,It can also bond with carbon
Dialogue: 0,0:07:16.81,0:07:17.91,Default,,0000,0000,0000,,which needs 4.
Dialogue: 0,0:07:17.91,0:07:21.56,Default,,0000,0000,0000,,So you get 2 double bonds to 2 different oxygen\Natoms and you end up with CO2.
Dialogue: 0,0:07:21.56,0:07:26.45,Default,,0000,0000,0000,,That pesky global warming gas and also the\Nstuff that makes all life on Earth possible.
Dialogue: 0,0:07:26.45,0:07:29.81,Default,,0000,0000,0000,,Nitrogen has 5 electrons in its outer shell.\NHere's how we count them:
Dialogue: 0,0:07:29.81,0:07:32.95,Default,,0000,0000,0000,,There are 4 placeholders. Each of them wants\N2 atoms.
Dialogue: 0,0:07:32.95,0:07:37.35,Default,,0000,0000,0000,,And like people getting on a bus they prefer\Nto start out not sitting next to each other.
Dialogue: 0,0:07:37.35,0:07:41.05,Default,,0000,0000,0000,,I'm not kidding about this, they really don't\Ndouble up until they have to.
Dialogue: 0,0:07:41.05,0:07:44.81,Default,,0000,0000,0000,,So for maximum happiness, nitrogen bonds with\N3 hydrogens, forming ammonia.
Dialogue: 0,0:07:44.81,0:07:49.38,Default,,0000,0000,0000,,Or with 2 hydrogens sticking off another group\Nof atoms, which we call an amino group.
Dialogue: 0,0:07:49.38,0:07:54.49,Default,,0000,0000,0000,,And if that amino group is bonded to a carbon\Nthat is bonded to a carboxylic acid group
Dialogue: 0,0:07:54.49,0:07:56.68,Default,,0000,0000,0000,,then you have
Dialogue: 0,0:07:56.68,0:07:57.57,Default,,0000,0000,0000,,an amino acid!
Dialogue: 0,0:07:57.57,0:07:59.15,Default,,0000,0000,0000,,You've heard of those, right?
Dialogue: 0,0:07:59.15,0:08:03.86,Default,,0000,0000,0000,,Sometimes electrons are shared equally within\Na covalent bond like with O2.
Dialogue: 0,0:08:03.86,0:08:09.01,Default,,0000,0000,0000,,That's called a non-polar covalent bond. But\Noften one of the participants is more greedy.
Dialogue: 0,0:08:09.01,0:08:12.45,Default,,0000,0000,0000,,In water for example, the oxygen molecule\Nsucks the electrons in
Dialogue: 0,0:08:12.45,0:08:15.65,Default,,0000,0000,0000,,and they spend more time with the oxygen than\Nwith the hydrogens.
Dialogue: 0,0:08:15.65,0:08:18.06,Default,,0000,0000,0000,,This creates a slight positive charge around\Nthe hydrogens
Dialogue: 0,0:08:18.06,0:08:20.31,Default,,0000,0000,0000,,and a slight negative charge around the oxygen.
Dialogue: 0,0:08:20.31,0:08:25.42,Default,,0000,0000,0000,,When something has a charge we say that it's\Npolar. It has a positive and negative pole.
Dialogue: 0,0:08:25.42,0:08:27.15,Default,,0000,0000,0000,,And so it's a polar covalent bond.
Dialogue: 0,0:08:27.15,0:08:31.11,Default,,0000,0000,0000,,Now let's talk for a moment about a completely\Ndifferent type of bond, which is an ionic
Dialogue: 0,0:08:31.11,0:08:31.61,Default,,0000,0000,0000,,bond.
Dialogue: 0,0:08:31.61,0:08:34.29,Default,,0000,0000,0000,,And that's when, instead of sharing electrons
Dialogue: 0,0:08:34.29,0:08:39.06,Default,,0000,0000,0000,,atoms just completely wholeheartedly donate\Nor accept an electron from another atom
Dialogue: 0,0:08:39.06,0:08:41.55,Default,,0000,0000,0000,,and then live happily as a charged atom.
Dialogue: 0,0:08:41.55,0:08:43.58,Default,,0000,0000,0000,,And there is actually no such thing as a charged\Natom.
Dialogue: 0,0:08:43.58,0:08:46.16,Default,,0000,0000,0000,,If an atom has a charge, it's an ion.
Dialogue: 0,0:08:46.16,0:08:50.61,Default,,0000,0000,0000,,Atoms in general prefer to be neutral, but\Ncompared with having a full octet, it's not
Dialogue: 0,0:08:50.61,0:08:51.32,Default,,0000,0000,0000,,that big of a deal.
Dialogue: 0,0:08:51.32,0:08:56.29,Default,,0000,0000,0000,,Just like we often choose between being emotionally\Nbalanced and sexually satisfied
Dialogue: 0,0:08:56.29,0:08:59.85,Default,,0000,0000,0000,,atoms will sometimes make sacrifices for that\Noctet.
Dialogue: 0,0:08:59.85,0:09:04.24,Default,,0000,0000,0000,,The most common ionic compound in our daily\Nlives is salt.
Dialogue: 0,0:09:04.24,0:09:05.55,Default,,0000,0000,0000,,Sodium chloride. NaCl.
Dialogue: 0,0:09:05.55,0:09:09.15,Default,,0000,0000,0000,,The stuff, despite it's deliciousness, as\NI mentioned previously
Dialogue: 0,0:09:09.15,0:09:13.45,Default,,0000,0000,0000,,is made up of two really nasty chemicals.\NSodium and chlorine.
Dialogue: 0,0:09:13.45,0:09:17.11,Default,,0000,0000,0000,,Chlorine is what we call a halogen, which\Nis an element that only needs one electron
Dialogue: 0,0:09:17.11,0:09:18.19,Default,,0000,0000,0000,,to fulfill it's octet.
Dialogue: 0,0:09:18.19,0:09:23.33,Default,,0000,0000,0000,,And sodium is an alkaline metal which means\Nthat it only has one electron in it's octet.
Dialogue: 0,0:09:23.33,0:09:26.46,Default,,0000,0000,0000,,So chlorine and sodium are so close to being\Nsatisfied
Dialogue: 0,0:09:26.46,0:09:32.42,Default,,0000,0000,0000,,that they will happily destroy anything in\Ntheir path in order to fulfill their octet.
Dialogue: 0,0:09:32.42,0:09:36.03,Default,,0000,0000,0000,,And thus, there's actually no better outcome\Nthan just to get
Dialogue: 0,0:09:36.03,0:09:38.93,Default,,0000,0000,0000,,chlorine and sodium together and have them\Nlovin' on each other.
Dialogue: 0,0:09:38.93,0:09:40.65,Default,,0000,0000,0000,,They immediately transfer their electrons.
Dialogue: 0,0:09:40.65,0:09:44.20,Default,,0000,0000,0000,,So that sodium doesn't have it's one extra,\Nand chlorine fills it's octet.
Dialogue: 0,0:09:44.20,0:09:48.09,Default,,0000,0000,0000,,They become Na+ and Cl- and are so charged\Nthat they stick together
Dialogue: 0,0:09:48.09,0:09:50.70,Default,,0000,0000,0000,,and we call that stickiness an ionic bond.
Dialogue: 0,0:09:50.70,0:09:53.53,Default,,0000,0000,0000,,And just like if you have two really crazy\Nfriends
Dialogue: 0,0:09:53.53,0:09:57.71,Default,,0000,0000,0000,,it might be good to get them together so that\Nthey'll stop bothering you.
Dialogue: 0,0:09:57.71,0:09:59.19,Default,,0000,0000,0000,,Same thing works with sodium and chlorine.
Dialogue: 0,0:09:59.19,0:10:01.84,Default,,0000,0000,0000,,You get those two together, and they'll bother\Nno one.
Dialogue: 0,0:10:01.84,0:10:04.72,Default,,0000,0000,0000,,And suddenly, they don't want to destroy,\Nthey just want to be delicious.
Dialogue: 0,0:10:04.72,0:10:06.99,Default,,0000,0000,0000,,Chemical changes like this are a big deal.
Dialogue: 0,0:10:06.99,0:10:10.65,Default,,0000,0000,0000,,Remember, chlorine and sodium, just a second\Nago, were definitely killing you, and now
Dialogue: 0,0:10:10.65,0:10:11.53,Default,,0000,0000,0000,,they're tasty.
Dialogue: 0,0:10:11.53,0:10:14.93,Default,,0000,0000,0000,,Now we're coming to the last bond that we're\Ngoing to discuss
Dialogue: 0,0:10:14.93,0:10:18.70,Default,,0000,0000,0000,,in our intro to chemistry here and that's\Nthe hydrogen bond.
Dialogue: 0,0:10:18.70,0:10:22.29,Default,,0000,0000,0000,,Imagine that you remember water, I hope that\Nyou didn't forget water.
Dialogue: 0,0:10:22.29,0:10:25.32,Default,,0000,0000,0000,,Since water is stuck together in a polar covalent\Nbond
Dialogue: 0,0:10:25.32,0:10:29.33,Default,,0000,0000,0000,,the hydrogen bit is positively charge and\Nthe oxygen bit is negatively charged.
Dialogue: 0,0:10:29.33,0:10:30.72,Default,,0000,0000,0000,,So when water molecules are moving around
Dialogue: 0,0:10:30.72,0:10:34.10,Default,,0000,0000,0000,,we generally think of them as a perfect fluid\Nbut they actually stick together a little
Dialogue: 0,0:10:34.10,0:10:34.88,Default,,0000,0000,0000,,bit.
Dialogue: 0,0:10:34.88,0:10:36.28,Default,,0000,0000,0000,,Hydrogen side to oxygen side.
Dialogue: 0,0:10:36.28,0:10:40.89,Default,,0000,0000,0000,,You can actually see this with your eyes if\Nyou fill up a glass of water too full
Dialogue: 0,0:10:40.89,0:10:45.31,Default,,0000,0000,0000,,it will bubble at the top. The water will\Nstick together at the top.
Dialogue: 0,0:10:45.31,0:10:50.06,Default,,0000,0000,0000,,That's the polar covalent bonds sticking the\Nwater molecules to each other
Dialogue: 0,0:10:50.06,0:10:52.55,Default,,0000,0000,0000,,so that they don't flow right over the top\Nof the glass.
Dialogue: 0,0:10:52.55,0:10:56.14,Default,,0000,0000,0000,,These relatively weak hydrogen bonds happen\Nin all sorts of chemical compounds
Dialogue: 0,0:10:56.14,0:11:00.20,Default,,0000,0000,0000,,they don't just happen in water. An they actually\Nplay an extremely important role in proteins
Dialogue: 0,0:11:00.20,0:11:04.05,Default,,0000,0000,0000,,which are the chemicals that pretty much up\Nour entire bodies.
Dialogue: 0,0:11:04.05,0:11:07.83,Default,,0000,0000,0000,,A final thing to note here is that bonds,\Neven covalent bonds, ionic bonds
Dialogue: 0,0:11:07.83,0:11:09.23,Default,,0000,0000,0000,,even with their own class
Dialogue: 0,0:11:09.23,0:11:11.76,Default,,0000,0000,0000,,are often much different strengths.
Dialogue: 0,0:11:11.76,0:11:15.30,Default,,0000,0000,0000,,And we tend to just write them with a little\Nline
Dialogue: 0,0:11:15.30,0:11:20.49,Default,,0000,0000,0000,,but that line can represent a very very strong\Ncovalent bond or a relatively weak covalent
Dialogue: 0,0:11:20.49,0:11:20.99,Default,,0000,0000,0000,,bond.
Dialogue: 0,0:11:20.99,0:11:23.11,Default,,0000,0000,0000,,Sometimes ionic bonds are stronger than covalent\Nbonds
Dialogue: 0,0:11:23.11,0:11:28.07,Default,,0000,0000,0000,,though that's generally not the case and the\Nstrength of covalent bonds varies wildly.
Dialogue: 0,0:11:28.07,0:11:33.18,Default,,0000,0000,0000,,How these bonds are made and broken is intensely\Nimportant to life.
Dialogue: 0,0:11:33.18,0:11:37.72,Default,,0000,0000,0000,,And to our lives. Making and breaking bonds\Nis in fact the key to life itself
Dialogue: 0,0:11:37.72,0:11:43.30,Default,,0000,0000,0000,,and also the key to death. For example, if\Nyou were to ingest some sodium metal.
Dialogue: 0,0:11:43.30,0:11:45.57,Default,,0000,0000,0000,,Keep this in mind as we move forward through\Nbiology:
Dialogue: 0,0:11:45.57,0:11:48.54,Default,,0000,0000,0000,,Even the sexiest person you have ever met\Nin your life
Dialogue: 0,0:11:48.54,0:11:55.53,Default,,0000,0000,0000,,is just a collection of organic compounds\Nrambling around in a sack of water.
Dialogue: 0,0:11:55.53,0:11:56.36,Default,,0000,0000,0000,,Review time!
Dialogue: 0,0:11:56.36,0:11:58.15,Default,,0000,0000,0000,,Now we have the table of contents
Dialogue: 0,0:11:58.15,0:12:00.08,Default,,0000,0000,0000,,Which I know is supposed to come at the beginning\Nof things
Dialogue: 0,0:12:00.08,0:12:03.84,Default,,0000,0000,0000,,But we are revolutionary here we're doing\Nit different
Dialogue: 0,0:12:03.84,0:12:05.87,Default,,0000,0000,0000,,so you can click on any of the things here
Dialogue: 0,0:12:05.87,0:12:09.56,Default,,0000,0000,0000,,and you can go back and review what you learned.
Dialogue: 0,0:12:09.56,0:12:10.84,Default,,0000,0000,0000,,Or didn't learn.
Dialogue: 0,0:12:10.84,0:12:14.14,Default,,0000,0000,0000,,And if you have questions please please please\Nplease please please please
Dialogue: 0,0:12:14.14,0:12:18.63,Default,,0000,0000,0000,,ask them in the comments and we'll be down\Nthere answering them for you.
Dialogue: 0,0:12:18.63,0:12:22.38,Default,,0000,0000,0000,,So thank you for joining us.
Dialogue: 0,0:12:22.38,0:12:24.66,Default,,0000,0000,0000,,It was a pleasure, it was a pleasure working\Nwith you today.