[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:00.69,Default,,0000,0000,0000,,
Dialogue: 0,0:00:00.69,0:00:03.66,Default,,0000,0000,0000,,SAL: Everything we've been\Ndealing with so far in our
Dialogue: 0,0:00:03.66,0:00:06.41,Default,,0000,0000,0000,,journey through chemistry has\Nrevolved around stability of
Dialogue: 0,0:00:06.41,0:00:08.42,Default,,0000,0000,0000,,electrons and where electrons\Nwould rather
Dialogue: 0,0:00:08.42,0:00:10.34,Default,,0000,0000,0000,,be in stable shells.
Dialogue: 0,0:00:10.34,0:00:14.03,Default,,0000,0000,0000,,And like all things in life,\Nif you explore the atom a
Dialogue: 0,0:00:14.03,0:00:16.40,Default,,0000,0000,0000,,little further you'll realize\Nthat electrons are not the
Dialogue: 0,0:00:16.40,0:00:19.25,Default,,0000,0000,0000,,only stuff that's going\Non in an atom.
Dialogue: 0,0:00:19.25,0:00:24.25,Default,,0000,0000,0000,,That the nucleus itself has some\Ninteractions, or has some
Dialogue: 0,0:00:24.25,0:00:27.14,Default,,0000,0000,0000,,instability, that needs to\Nbe relieved in some way.
Dialogue: 0,0:00:27.14,0:00:28.74,Default,,0000,0000,0000,,That's what we'll talk\Na little bit
Dialogue: 0,0:00:28.74,0:00:31.42,Default,,0000,0000,0000,,about in this video.
Dialogue: 0,0:00:31.42,0:00:35.11,Default,,0000,0000,0000,,And actually the mechanics of\Nit are well out of the scope
Dialogue: 0,0:00:35.11,0:00:37.45,Default,,0000,0000,0000,,of a first-year chemistry\Ncourse, but it's good to at
Dialogue: 0,0:00:37.45,0:00:39.57,Default,,0000,0000,0000,,least know that it occurs.
Dialogue: 0,0:00:39.57,0:00:43.11,Default,,0000,0000,0000,,And one day when we study the\Nstrong nuclear force, and
Dialogue: 0,0:00:43.11,0:00:45.57,Default,,0000,0000,0000,,quantum physics, and all the\Nlike, then we can start
Dialogue: 0,0:00:45.57,0:00:49.28,Default,,0000,0000,0000,,talking about exactly why these\Nprotons and neutrons,
Dialogue: 0,0:00:49.28,0:00:52.81,Default,,0000,0000,0000,,and their constituent quarks\Nare interacting
Dialogue: 0,0:00:52.81,0:00:53.53,Default,,0000,0000,0000,,the way they do.
Dialogue: 0,0:00:53.53,0:00:55.50,Default,,0000,0000,0000,,But with that said, let's\Nat least think about the
Dialogue: 0,0:00:55.50,0:01:00.89,Default,,0000,0000,0000,,different types of ways that a\Nnucleus can essentially decay.
Dialogue: 0,0:01:00.89,0:01:03.88,Default,,0000,0000,0000,,So let's say I have a\Nbunch of protons.
Dialogue: 0,0:01:03.88,0:01:06.83,Default,,0000,0000,0000,,I'll just draw a couple here.
Dialogue: 0,0:01:06.83,0:01:09.59,Default,,0000,0000,0000,,Some protons there, and I'll\Ndraw some neutrons.
Dialogue: 0,0:01:09.59,0:01:13.43,Default,,0000,0000,0000,,And I'll draw them in\Na neutral-ish color.
Dialogue: 0,0:01:13.43,0:01:16.78,Default,,0000,0000,0000,,Maybe let me see, like a\Ngrayish would be good.
Dialogue: 0,0:01:16.78,0:01:21.52,Default,,0000,0000,0000,,So let me just draw some\Nneutrons here.
Dialogue: 0,0:01:21.52,0:01:22.02,Default,,0000,0000,0000,,How many protons do I have?
Dialogue: 0,0:01:22.02,0:01:24.30,Default,,0000,0000,0000,,I have 1, 2, 3, 4, 5, 6, 7, 8.
Dialogue: 0,0:01:24.30,0:01:32.41,Default,,0000,0000,0000,,I'll do 1, 2, 3, 4, 5,\N6, 7, 8, 9 neutrons.
Dialogue: 0,0:01:32.41,0:01:34.87,Default,,0000,0000,0000,,And so let's say this is the\Nnucleus of our atom.
Dialogue: 0,0:01:34.87,0:01:36.96,Default,,0000,0000,0000,,And remember-- and this is, you\Nknow, in the very first
Dialogue: 0,0:01:36.96,0:01:39.86,Default,,0000,0000,0000,,video I made about the atom--\Nthe nucleus, if you actually
Dialogue: 0,0:01:39.86,0:01:43.32,Default,,0000,0000,0000,,were to draw an actual atom--\Nand it's actually very hard to
Dialogue: 0,0:01:43.32,0:01:45.44,Default,,0000,0000,0000,,drawn an atom because it has\Nno well-defined boundaries.
Dialogue: 0,0:01:45.44,0:01:49.05,Default,,0000,0000,0000,,The electron really could be,\Nyou know, at any given moment,
Dialogue: 0,0:01:49.05,0:01:49.98,Default,,0000,0000,0000,,it could be anywhere.
Dialogue: 0,0:01:49.98,0:01:52.74,Default,,0000,0000,0000,,But if you were to say, OK,\Nwhere is 90% of the time the
Dialogue: 0,0:01:52.74,0:01:53.70,Default,,0000,0000,0000,,electron is going to be in?
Dialogue: 0,0:01:53.70,0:01:55.68,Default,,0000,0000,0000,,You'd say, that's the radius,\Nor that's the
Dialogue: 0,0:01:55.68,0:01:57.75,Default,,0000,0000,0000,,diameter of our atom.
Dialogue: 0,0:01:57.75,0:02:00.53,Default,,0000,0000,0000,,We learned in that very first\Nvideo that the nucleus is
Dialogue: 0,0:02:00.53,0:02:05.45,Default,,0000,0000,0000,,almost an infinitesimal portion\Nof the volume of this
Dialogue: 0,0:02:05.45,0:02:08.34,Default,,0000,0000,0000,,sphere where the electron\Nwill be 90% of the time.
Dialogue: 0,0:02:08.34,0:02:12.08,Default,,0000,0000,0000,,And the neat takeaway there\Nwas that, well, most of
Dialogue: 0,0:02:12.08,0:02:15.28,Default,,0000,0000,0000,,whatever we look at in life\Nis just open free space.
Dialogue: 0,0:02:15.28,0:02:17.03,Default,,0000,0000,0000,,All of this is just\Nopen space.
Dialogue: 0,0:02:17.03,0:02:19.40,Default,,0000,0000,0000,,But I just want to repeat\Nthat because that little
Dialogue: 0,0:02:19.40,0:02:23.66,Default,,0000,0000,0000,,infinitesimal spot that we\Ntalked about before, where
Dialogue: 0,0:02:23.66,0:02:26.32,Default,,0000,0000,0000,,even though it's a very small\Npart of the fraction of the
Dialogue: 0,0:02:26.32,0:02:29.03,Default,,0000,0000,0000,,volume of an atom-- it's\Nactually almost all of its
Dialogue: 0,0:02:29.03,0:02:31.89,Default,,0000,0000,0000,,mass-- that's what I'm zooming\Nout to this point here.
Dialogue: 0,0:02:31.89,0:02:34.24,Default,,0000,0000,0000,,These aren't atoms, these\Naren't electrons.
Dialogue: 0,0:02:34.24,0:02:36.58,Default,,0000,0000,0000,,We're zoomed into the nucleus.
Dialogue: 0,0:02:36.58,0:02:40.04,Default,,0000,0000,0000,,And so it turns out that\Nsometimes the nucleus is a
Dialogue: 0,0:02:40.04,0:02:43.65,Default,,0000,0000,0000,,little bit unstable, and it\Nwants to get to a more stable
Dialogue: 0,0:02:43.65,0:02:44.40,Default,,0000,0000,0000,,configuration.
Dialogue: 0,0:02:44.40,0:02:46.60,Default,,0000,0000,0000,,We're not going to go into the\Nmechanics of exactly what
Dialogue: 0,0:02:46.60,0:02:48.70,Default,,0000,0000,0000,,defines an unstable nucleus\Nand all that.
Dialogue: 0,0:02:48.70,0:02:51.88,Default,,0000,0000,0000,,But in order to get into a\Nmore unstable nucleus,
Dialogue: 0,0:02:51.88,0:02:55.82,Default,,0000,0000,0000,,sometimes it emits what's called\Nan alpha particle, or
Dialogue: 0,0:02:55.82,0:02:58.47,Default,,0000,0000,0000,,this is called alpha decay.
Dialogue: 0,0:02:58.47,0:03:04.44,Default,,0000,0000,0000,,Alpha decay.
Dialogue: 0,0:03:04.44,0:03:06.22,Default,,0000,0000,0000,,And it emits an alpha particle,
Dialogue: 0,0:03:06.22,0:03:09.16,Default,,0000,0000,0000,,which sounds very fancy.
Dialogue: 0,0:03:09.16,0:03:12.45,Default,,0000,0000,0000,,It's just a collection of\Nneutrons and protons.
Dialogue: 0,0:03:12.45,0:03:16.69,Default,,0000,0000,0000,,So an alpha particle is two\Nneutrons and two protons.
Dialogue: 0,0:03:16.69,0:03:20.85,Default,,0000,0000,0000,,So maybe these guys, they just\Ndidn't feel like they'd fit in
Dialogue: 0,0:03:20.85,0:03:25.11,Default,,0000,0000,0000,,just right, so they're a\Ncollection right here.
Dialogue: 0,0:03:25.11,0:03:27.74,Default,,0000,0000,0000,,And they get emitted.
Dialogue: 0,0:03:27.74,0:03:30.07,Default,,0000,0000,0000,,They leave the nucleus.
Dialogue: 0,0:03:30.07,0:03:33.87,Default,,0000,0000,0000,,So let's just think what\Nhappens to an atom when
Dialogue: 0,0:03:33.87,0:03:36.05,Default,,0000,0000,0000,,something like that happens.
Dialogue: 0,0:03:36.05,0:03:38.50,Default,,0000,0000,0000,,So let's just say I have some\Nrandom element, I'll just call
Dialogue: 0,0:03:38.50,0:03:40.31,Default,,0000,0000,0000,,it element E.
Dialogue: 0,0:03:40.31,0:03:43.02,Default,,0000,0000,0000,,Let's say it has p, protons.
Dialogue: 0,0:03:43.02,0:03:45.66,Default,,0000,0000,0000,,Actually let me do it in the\Ncolor of my protons.
Dialogue: 0,0:03:45.66,0:03:47.80,Default,,0000,0000,0000,,It has p, protons.
Dialogue: 0,0:03:47.80,0:03:51.55,Default,,0000,0000,0000,,And then it has its atomic mass\Nnumber, is the number of
Dialogue: 0,0:03:51.55,0:03:55.51,Default,,0000,0000,0000,,protons plus the number\Nof neutrons.
Dialogue: 0,0:03:55.51,0:03:59.48,Default,,0000,0000,0000,,And do the neutrons\Nin gray, right?
Dialogue: 0,0:03:59.48,0:04:06.59,Default,,0000,0000,0000,,So when it experiences\Nalpha decay, what
Dialogue: 0,0:04:06.59,0:04:08.18,Default,,0000,0000,0000,,happens to the element?
Dialogue: 0,0:04:08.18,0:04:11.89,Default,,0000,0000,0000,,Well, its protons are going\Nto decrease by two.
Dialogue: 0,0:04:11.89,0:04:16.04,Default,,0000,0000,0000,,So its protons are going\Nto be p minus 2.
Dialogue: 0,0:04:16.04,0:04:19.45,Default,,0000,0000,0000,,And then its neutrons are also\Ngoing to decrease by two.
Dialogue: 0,0:04:19.45,0:04:21.32,Default,,0000,0000,0000,,So its mass number's going\Nto decrease by four.
Dialogue: 0,0:04:21.32,0:04:27.10,Default,,0000,0000,0000,,So up here you'll have p minus\N2, plus our neutrons minus 2,
Dialogue: 0,0:04:27.10,0:04:28.94,Default,,0000,0000,0000,,so we're going to\Nhave minus 4.
Dialogue: 0,0:04:28.94,0:04:31.08,Default,,0000,0000,0000,,So your mass is going to\Ndecrease by four, and you're
Dialogue: 0,0:04:31.08,0:04:32.70,Default,,0000,0000,0000,,actually going to turn\Nto a new element.
Dialogue: 0,0:04:32.70,0:04:34.71,Default,,0000,0000,0000,,Remember, your elements\Nwere defined by
Dialogue: 0,0:04:34.71,0:04:36.25,Default,,0000,0000,0000,,the number of protons.
Dialogue: 0,0:04:36.25,0:04:40.63,Default,,0000,0000,0000,,So in this alpha decay, when\Nyou're losing two neutrons and
Dialogue: 0,0:04:40.63,0:04:43.30,Default,,0000,0000,0000,,two protons, but especially the\Nprotons are going to make
Dialogue: 0,0:04:43.30,0:04:44.46,Default,,0000,0000,0000,,you into a different element.
Dialogue: 0,0:04:44.46,0:04:46.86,Default,,0000,0000,0000,,So if we call this element 1,\NI'm just going to call it,
Dialogue: 0,0:04:46.86,0:04:50.59,Default,,0000,0000,0000,,we're going to be a different\Nelement now, element 2.
Dialogue: 0,0:04:50.59,0:04:54.05,Default,,0000,0000,0000,,And if you think about what's\Ngenerated, we're emitting
Dialogue: 0,0:04:54.05,0:04:58.60,Default,,0000,0000,0000,,something that has two protons,
Dialogue: 0,0:04:58.60,0:05:00.34,Default,,0000,0000,0000,,and it has two neutrons.
Dialogue: 0,0:05:00.34,0:05:02.74,Default,,0000,0000,0000,,So that its mass is going to be\Nthe mass of the two protons
Dialogue: 0,0:05:02.74,0:05:04.79,Default,,0000,0000,0000,,and two neutrons.
Dialogue: 0,0:05:04.79,0:05:05.83,Default,,0000,0000,0000,,So what are we emitting?
Dialogue: 0,0:05:05.83,0:05:09.81,Default,,0000,0000,0000,,We're emitting something that\Nhas a mass of four.
Dialogue: 0,0:05:09.81,0:05:12.17,Default,,0000,0000,0000,,So if you look at, what is two\Nprotons and two neutrons?
Dialogue: 0,0:05:12.17,0:05:14.74,Default,,0000,0000,0000,,I actually don't have the\Nperiodic table on my
Dialogue: 0,0:05:14.74,0:05:14.88,Default,,0000,0000,0000,,[? head. ?]
Dialogue: 0,0:05:14.88,0:05:17.02,Default,,0000,0000,0000,,I forgot to cut and paste\Nit before this video.
Dialogue: 0,0:05:17.02,0:05:19.68,Default,,0000,0000,0000,,But it doesn't take you long on\Nthe periodic table to find
Dialogue: 0,0:05:19.68,0:05:23.28,Default,,0000,0000,0000,,an element that has two protons,\Nand that's helium.
Dialogue: 0,0:05:23.28,0:05:25.59,Default,,0000,0000,0000,,It actually has an atomic\Nmass of four.
Dialogue: 0,0:05:25.59,0:05:29.39,Default,,0000,0000,0000,,So this is actually a helium\Nnucleus that gets emitted with
Dialogue: 0,0:05:29.39,0:05:30.08,Default,,0000,0000,0000,,alpha decay.
Dialogue: 0,0:05:30.08,0:05:31.88,Default,,0000,0000,0000,,This is actually a\Nhelium nucleus.
Dialogue: 0,0:05:31.88,0:05:35.01,Default,,0000,0000,0000,,
Dialogue: 0,0:05:35.01,0:05:39.17,Default,,0000,0000,0000,,And because it's a helium\Nnucleus and it has no
Dialogue: 0,0:05:39.17,0:05:43.42,Default,,0000,0000,0000,,electrons to bounce off its two\Nprotons, this would be a
Dialogue: 0,0:05:43.42,0:05:44.95,Default,,0000,0000,0000,,helium ion.
Dialogue: 0,0:05:44.95,0:05:48.49,Default,,0000,0000,0000,,So essentially it has\Nno electrons.
Dialogue: 0,0:05:48.49,0:05:50.83,Default,,0000,0000,0000,,It has two protons so it\Nhas a plus 2 charge.
Dialogue: 0,0:05:50.83,0:05:53.35,Default,,0000,0000,0000,,
Dialogue: 0,0:05:53.35,0:05:59.11,Default,,0000,0000,0000,,So an alpha particle is really\Njust a helium ion, a plus 2
Dialogue: 0,0:05:59.11,0:06:01.96,Default,,0000,0000,0000,,charged helium ion that is\Nspontaneously emitted by a
Dialogue: 0,0:06:01.96,0:06:05.78,Default,,0000,0000,0000,,nucleus just to get to\Na more stable state.
Dialogue: 0,0:06:05.78,0:06:07.67,Default,,0000,0000,0000,,Now that's one type of decay.
Dialogue: 0,0:06:07.67,0:06:08.85,Default,,0000,0000,0000,,Let's explore the other ones.
Dialogue: 0,0:06:08.85,0:06:14.05,Default,,0000,0000,0000,,So let me draw another\Nnucleus here.
Dialogue: 0,0:06:14.05,0:06:17.64,Default,,0000,0000,0000,,I'll draw some neutrons.
Dialogue: 0,0:06:17.64,0:06:19.31,Default,,0000,0000,0000,,I'll just draw some protons.
Dialogue: 0,0:06:19.31,0:06:24.20,Default,,0000,0000,0000,,
Dialogue: 0,0:06:24.20,0:06:27.92,Default,,0000,0000,0000,,So it turns out sometimes that\Na neutron doesn't feel
Dialogue: 0,0:06:27.92,0:06:30.71,Default,,0000,0000,0000,,comfortable with itself.
Dialogue: 0,0:06:30.71,0:06:33.71,Default,,0000,0000,0000,,It looks at what the protons do\Non a daily basis and says,
Dialogue: 0,0:06:33.71,0:06:34.56,Default,,0000,0000,0000,,you know what?
Dialogue: 0,0:06:34.56,0:06:37.78,Default,,0000,0000,0000,,For some reason when I look into\Nmy heart, I feel like I
Dialogue: 0,0:06:37.78,0:06:39.22,Default,,0000,0000,0000,,really should be a proton.
Dialogue: 0,0:06:39.22,0:06:42.64,Default,,0000,0000,0000,,If I were a proton, the entire\Nnucleus would be a little bit
Dialogue: 0,0:06:42.64,0:06:43.87,Default,,0000,0000,0000,,more stable.
Dialogue: 0,0:06:43.87,0:06:46.86,Default,,0000,0000,0000,,And so what it does is, to\Nbecome a proton-- remember, a
Dialogue: 0,0:06:46.86,0:06:49.18,Default,,0000,0000,0000,,neutron has neutral charge.
Dialogue: 0,0:06:49.18,0:06:52.06,Default,,0000,0000,0000,,So what it does is, it\Nemits an electron.
Dialogue: 0,0:06:52.06,0:06:54.07,Default,,0000,0000,0000,,And I know you're saying, Sal,\Nyou know, that's crazy, I
Dialogue: 0,0:06:54.07,0:06:55.76,Default,,0000,0000,0000,,didn't even know neutrons\Nhad electrons in
Dialogue: 0,0:06:55.76,0:06:56.90,Default,,0000,0000,0000,,them, and all of that.
Dialogue: 0,0:06:56.90,0:06:58.05,Default,,0000,0000,0000,,And I agree with you.
Dialogue: 0,0:06:58.05,0:06:58.81,Default,,0000,0000,0000,,It is crazy.
Dialogue: 0,0:06:58.81,0:07:01.75,Default,,0000,0000,0000,,And one day we'll study\Nall of what exists
Dialogue: 0,0:07:01.75,0:07:03.54,Default,,0000,0000,0000,,inside of the nucleus.
Dialogue: 0,0:07:03.54,0:07:08.88,Default,,0000,0000,0000,,But let's just say that it\Ncan emit an electron.
Dialogue: 0,0:07:08.88,0:07:10.21,Default,,0000,0000,0000,,So this emits an electron.
Dialogue: 0,0:07:10.21,0:07:12.73,Default,,0000,0000,0000,,
Dialogue: 0,0:07:12.73,0:07:15.46,Default,,0000,0000,0000,,And we signify that with its--\Nroughly its mass is zero.
Dialogue: 0,0:07:15.46,0:07:17.83,Default,,0000,0000,0000,,We know an electron really\Ndoesn't have a zero mass, but
Dialogue: 0,0:07:17.83,0:07:19.97,Default,,0000,0000,0000,,we're talking about\Natomic mass units.
Dialogue: 0,0:07:19.97,0:07:25.13,Default,,0000,0000,0000,,If the proton is one, an\Nelectron is 1/1,836 of that.
Dialogue: 0,0:07:25.13,0:07:25.94,Default,,0000,0000,0000,,So we just round it.
Dialogue: 0,0:07:25.94,0:07:27.25,Default,,0000,0000,0000,,We say it has a mass of zero.
Dialogue: 0,0:07:27.25,0:07:29.38,Default,,0000,0000,0000,,Its mass really isn't zero.
Dialogue: 0,0:07:29.38,0:07:32.67,Default,,0000,0000,0000,,And its charge is minus 1.
Dialogue: 0,0:07:32.67,0:07:34.37,Default,,0000,0000,0000,,It's atomic, you can kind\Nof say its atomic
Dialogue: 0,0:07:34.37,0:07:35.20,Default,,0000,0000,0000,,number's minus 1.
Dialogue: 0,0:07:35.20,0:07:36.57,Default,,0000,0000,0000,,So it emits an electron.
Dialogue: 0,0:07:36.57,0:07:39.76,Default,,0000,0000,0000,,And by emitting an electron,\Ninstead of being neutral, now
Dialogue: 0,0:07:39.76,0:07:41.02,Default,,0000,0000,0000,,it turns into a proton.
Dialogue: 0,0:07:41.02,0:07:44.49,Default,,0000,0000,0000,,
Dialogue: 0,0:07:44.49,0:07:47.09,Default,,0000,0000,0000,,And so this is called\Nbeta decay.
Dialogue: 0,0:07:47.09,0:07:52.50,Default,,0000,0000,0000,,
Dialogue: 0,0:07:52.50,0:07:56.78,Default,,0000,0000,0000,,And a beta particle is really\Njust that emitted electron.
Dialogue: 0,0:07:56.78,0:08:00.48,Default,,0000,0000,0000,,So let's go back to our little\Ncase of an element.
Dialogue: 0,0:08:00.48,0:08:03.94,Default,,0000,0000,0000,,It has some number of protons,\Nand then it has
Dialogue: 0,0:08:03.94,0:08:05.98,Default,,0000,0000,0000,,some number of neutrons.
Dialogue: 0,0:08:05.98,0:08:08.34,Default,,0000,0000,0000,,So you have the protons and\Nthe neutrons, then you get
Dialogue: 0,0:08:08.34,0:08:09.66,Default,,0000,0000,0000,,your mass number.
Dialogue: 0,0:08:09.66,0:08:13.48,Default,,0000,0000,0000,,When it experiences beta\Ndecay, what happens?
Dialogue: 0,0:08:13.48,0:08:15.49,Default,,0000,0000,0000,,Well, are the protons changed?
Dialogue: 0,0:08:15.49,0:08:18.89,Default,,0000,0000,0000,,Sure, we have one more proton\Nthan we had before.
Dialogue: 0,0:08:18.89,0:08:20.50,Default,,0000,0000,0000,,Because our neutron\Nchanged into one.
Dialogue: 0,0:08:20.50,0:08:23.41,Default,,0000,0000,0000,,So now our protons are plus 1.
Dialogue: 0,0:08:23.41,0:08:25.19,Default,,0000,0000,0000,,Has our mass number changed?
Dialogue: 0,0:08:25.19,0:08:26.72,Default,,0000,0000,0000,,Well let's see.
Dialogue: 0,0:08:26.72,0:08:28.75,Default,,0000,0000,0000,,The neutrons goes down\Nby one but your
Dialogue: 0,0:08:28.75,0:08:30.36,Default,,0000,0000,0000,,protons go up to by one.
Dialogue: 0,0:08:30.36,0:08:32.38,Default,,0000,0000,0000,,So your mass number\Nwill not change.
Dialogue: 0,0:08:32.38,0:08:36.79,Default,,0000,0000,0000,,So it's still going\Nto be p plus N.
Dialogue: 0,0:08:36.79,0:08:39.91,Default,,0000,0000,0000,,so your mass stays the same,\Nunlike the situation with
Dialogue: 0,0:08:39.91,0:08:42.68,Default,,0000,0000,0000,,alpha decay, but your\Nelement changes.
Dialogue: 0,0:08:42.68,0:08:44.04,Default,,0000,0000,0000,,Your number of protons\Nchanges.
Dialogue: 0,0:08:44.04,0:08:47.98,Default,,0000,0000,0000,,So now, once again, you're\Ndealing with a new element in
Dialogue: 0,0:08:47.98,0:08:49.47,Default,,0000,0000,0000,,beta decay.
Dialogue: 0,0:08:49.47,0:08:52.53,Default,,0000,0000,0000,,Now, let's say we have\Nthe other situation.
Dialogue: 0,0:08:52.53,0:08:57.36,Default,,0000,0000,0000,,Let's say we have a situation\Nwhere one of these protons
Dialogue: 0,0:08:57.36,0:09:00.75,Default,,0000,0000,0000,,looks at the neutrons and\Nsays, you know what?
Dialogue: 0,0:09:00.75,0:09:02.24,Default,,0000,0000,0000,,I see how they live.
Dialogue: 0,0:09:02.24,0:09:04.17,Default,,0000,0000,0000,,It's very appealing to me.
Dialogue: 0,0:09:04.17,0:09:13.91,Default,,0000,0000,0000,,I think I would fit in better,\Nand our community of particles
Dialogue: 0,0:09:13.91,0:09:15.66,Default,,0000,0000,0000,,within the nucleus would\Nbe happier if
Dialogue: 0,0:09:15.66,0:09:17.16,Default,,0000,0000,0000,,I too were a neutron.
Dialogue: 0,0:09:17.16,0:09:19.77,Default,,0000,0000,0000,,We'd all be in a more\Nstable condition.
Dialogue: 0,0:09:19.77,0:09:23.66,Default,,0000,0000,0000,,So what they do is, that little\Nuncomfortable proton
Dialogue: 0,0:09:23.66,0:09:27.34,Default,,0000,0000,0000,,has some probability of\Nemitting-- and now this is a
Dialogue: 0,0:09:27.34,0:09:31.02,Default,,0000,0000,0000,,new idea to you-- a positron,\Nnot a proton.
Dialogue: 0,0:09:31.02,0:09:33.07,Default,,0000,0000,0000,,It emits a positron.
Dialogue: 0,0:09:33.07,0:09:34.67,Default,,0000,0000,0000,,And what's a positron?
Dialogue: 0,0:09:34.67,0:09:36.39,Default,,0000,0000,0000,,It's something that\Nhas the exact
Dialogue: 0,0:09:36.39,0:09:38.61,Default,,0000,0000,0000,,same mass as an electron.
Dialogue: 0,0:09:38.61,0:09:42.89,Default,,0000,0000,0000,,So it's 1/1836 of the\Nmass of a proton.
Dialogue: 0,0:09:42.89,0:09:46.20,Default,,0000,0000,0000,,But we just write a zero there\Nbecause in atomic mass units
Dialogue: 0,0:09:46.20,0:09:47.83,Default,,0000,0000,0000,,it's pretty close to zero.
Dialogue: 0,0:09:47.83,0:09:50.01,Default,,0000,0000,0000,,But it has a positive charge.
Dialogue: 0,0:09:50.01,0:09:51.72,Default,,0000,0000,0000,,And it's a little confusing,\Nbecause they'll
Dialogue: 0,0:09:51.72,0:09:52.63,Default,,0000,0000,0000,,still write e there.
Dialogue: 0,0:09:52.63,0:09:54.44,Default,,0000,0000,0000,,Whenever I see an e, I\Nthink an electron.
Dialogue: 0,0:09:54.44,0:09:56.72,Default,,0000,0000,0000,,But no, they say e because it's\Nkind of like the same
Dialogue: 0,0:09:56.72,0:09:59.50,Default,,0000,0000,0000,,type of particle, but instead\Nof having a negative charge,
Dialogue: 0,0:09:59.50,0:10:00.83,Default,,0000,0000,0000,,it has a positive charge.
Dialogue: 0,0:10:00.83,0:10:02.08,Default,,0000,0000,0000,,This is a positron.
Dialogue: 0,0:10:02.08,0:10:04.98,Default,,0000,0000,0000,,
Dialogue: 0,0:10:04.98,0:10:08.45,Default,,0000,0000,0000,,And now we're starting to get\Nkind of exotic with the types
Dialogue: 0,0:10:08.45,0:10:10.21,Default,,0000,0000,0000,,of particles and stuff\Nwe're dealing with.
Dialogue: 0,0:10:10.21,0:10:11.73,Default,,0000,0000,0000,,But this does happen.
Dialogue: 0,0:10:11.73,0:10:15.92,Default,,0000,0000,0000,,And if you have a proton that\Nemits this particle, that
Dialogue: 0,0:10:15.92,0:10:19.37,Default,,0000,0000,0000,,pretty much had all of its\Npositive charge going with it,
Dialogue: 0,0:10:19.37,0:10:26.33,Default,,0000,0000,0000,,this proton turns\Ninto a neutron.
Dialogue: 0,0:10:26.33,0:10:29.16,Default,,0000,0000,0000,,And that is called positron\Nemission.
Dialogue: 0,0:10:29.16,0:10:31.35,Default,,0000,0000,0000,,Positron emission is usually\Npretty easy to figure out what
Dialogue: 0,0:10:31.35,0:10:33.51,Default,,0000,0000,0000,,it is, because they call\Nit positron emission.
Dialogue: 0,0:10:33.51,0:10:37.88,Default,,0000,0000,0000,,So if we start with the same E,\Nit has a certain number of
Dialogue: 0,0:10:37.88,0:10:41.50,Default,,0000,0000,0000,,protons, and a certain\Nnumber of neutrons.
Dialogue: 0,0:10:41.50,0:10:43.19,Default,,0000,0000,0000,,What's the new element\Ngoing to be?
Dialogue: 0,0:10:43.19,0:10:46.06,Default,,0000,0000,0000,,Well it's going to lose\Na proton. p minus 1.
Dialogue: 0,0:10:46.06,0:10:47.77,Default,,0000,0000,0000,,And that's going to be turned\Ninto a neutron.
Dialogue: 0,0:10:47.77,0:10:49.62,Default,,0000,0000,0000,,So p is going to\Ngo down by one.
Dialogue: 0,0:10:49.62,0:10:51.03,Default,,0000,0000,0000,,N is going to go up by one.
Dialogue: 0,0:10:51.03,0:10:55.02,Default,,0000,0000,0000,,So that the mass of the whole\Natom isn't going to change.
Dialogue: 0,0:10:55.02,0:10:57.55,Default,,0000,0000,0000,,So it's going to be p plus N.
Dialogue: 0,0:10:57.55,0:11:00.50,Default,,0000,0000,0000,,But we're still going to have\Na different element, right?
Dialogue: 0,0:11:00.50,0:11:03.23,Default,,0000,0000,0000,,When we had beta decay,\Nwe increased
Dialogue: 0,0:11:03.23,0:11:04.15,Default,,0000,0000,0000,,the number of protons.
Dialogue: 0,0:11:04.15,0:11:06.70,Default,,0000,0000,0000,,So we went, kind of, to the\Nright in the periodic table or
Dialogue: 0,0:11:06.70,0:11:09.07,Default,,0000,0000,0000,,we increased our, well,\Nyou get the idea.
Dialogue: 0,0:11:09.07,0:11:12.44,Default,,0000,0000,0000,,When we do positron emission,\Nwe decreased
Dialogue: 0,0:11:12.44,0:11:14.70,Default,,0000,0000,0000,,our number of protons.
Dialogue: 0,0:11:14.70,0:11:16.30,Default,,0000,0000,0000,,And actually I should\Nwrite that here in
Dialogue: 0,0:11:16.30,0:11:17.51,Default,,0000,0000,0000,,both of these reactions.
Dialogue: 0,0:11:17.51,0:11:20.46,Default,,0000,0000,0000,,So this is the positron\Nemission, and I'm left over
Dialogue: 0,0:11:20.46,0:11:22.06,Default,,0000,0000,0000,,with one positron.
Dialogue: 0,0:11:22.06,0:11:29.43,Default,,0000,0000,0000,,And in our beta decay, I'm left\Nover with one electron.
Dialogue: 0,0:11:29.43,0:11:30.67,Default,,0000,0000,0000,,They're written the\Nexact same way.
Dialogue: 0,0:11:30.67,0:11:32.66,Default,,0000,0000,0000,,You know this is an electron\Nbecause it's a minus 1 charge.
Dialogue: 0,0:11:32.66,0:11:33.89,Default,,0000,0000,0000,,You know this is a positron\Nbecause it
Dialogue: 0,0:11:33.89,0:11:35.81,Default,,0000,0000,0000,,has a plus 1 charge.
Dialogue: 0,0:11:35.81,0:11:38.17,Default,,0000,0000,0000,,Now there's one last\Ntype of decay that
Dialogue: 0,0:11:38.17,0:11:39.14,Default,,0000,0000,0000,,you should know about.
Dialogue: 0,0:11:39.14,0:11:42.81,Default,,0000,0000,0000,,But it doesn't change the number\Nof protons or neutrons
Dialogue: 0,0:11:42.81,0:11:43.97,Default,,0000,0000,0000,,in a nucleus.
Dialogue: 0,0:11:43.97,0:11:46.94,Default,,0000,0000,0000,,But it just releases a ton of\Nenergy, or sometimes, you
Dialogue: 0,0:11:46.94,0:11:48.35,Default,,0000,0000,0000,,know, a high-energy proton.
Dialogue: 0,0:11:48.35,0:11:50.16,Default,,0000,0000,0000,,And that's called gamma decay.
Dialogue: 0,0:11:50.16,0:11:52.51,Default,,0000,0000,0000,,And gamma decay means that these\Nguys just reconfigure
Dialogue: 0,0:11:52.51,0:11:52.80,Default,,0000,0000,0000,,themselves.
Dialogue: 0,0:11:52.80,0:11:54.46,Default,,0000,0000,0000,,Maybe they get a little\Nbit closer.
Dialogue: 0,0:11:54.46,0:11:57.99,Default,,0000,0000,0000,,And by doing that they release\Nenergy in the form of a very
Dialogue: 0,0:11:57.99,0:12:03.18,Default,,0000,0000,0000,,high wavelength electromagnetic\Nwave. Which is
Dialogue: 0,0:12:03.18,0:12:05.82,Default,,0000,0000,0000,,essentially a gamma, you could\Neither call it a gamma
Dialogue: 0,0:12:05.82,0:12:08.23,Default,,0000,0000,0000,,particle or gamma ray.
Dialogue: 0,0:12:08.23,0:12:09.45,Default,,0000,0000,0000,,And it's very high energy.
Dialogue: 0,0:12:09.45,0:12:11.72,Default,,0000,0000,0000,,Gamma rays are something you\Ndon't want to be around.
Dialogue: 0,0:12:11.72,0:12:15.46,Default,,0000,0000,0000,,They're very likely\Nto maybe kill you.
Dialogue: 0,0:12:15.46,0:12:17.13,Default,,0000,0000,0000,,Everything we did, I've said\Nis a little theoretical.
Dialogue: 0,0:12:17.13,0:12:20.00,Default,,0000,0000,0000,,Let's do some actual problems,\Nand figure out what type of
Dialogue: 0,0:12:20.00,0:12:21.75,Default,,0000,0000,0000,,decay we're dealing with.
Dialogue: 0,0:12:21.75,0:12:24.40,Default,,0000,0000,0000,,So here I have 7-beryllium\Nwhere seven
Dialogue: 0,0:12:24.40,0:12:26.90,Default,,0000,0000,0000,,is its atomic mass.
Dialogue: 0,0:12:26.90,0:12:30.52,Default,,0000,0000,0000,,And I have it being converted\Nto 7-lithium So
Dialogue: 0,0:12:30.52,0:12:31.44,Default,,0000,0000,0000,,what's going on here?
Dialogue: 0,0:12:31.44,0:12:36.00,Default,,0000,0000,0000,,My beryllium, my nuclear mass\Nis staying the same, but I'm
Dialogue: 0,0:12:36.00,0:12:42.24,Default,,0000,0000,0000,,going from four protons\Nto three protons.
Dialogue: 0,0:12:42.24,0:12:45.13,Default,,0000,0000,0000,,So I'm reducing my number\Nof protons.
Dialogue: 0,0:12:45.13,0:12:46.84,Default,,0000,0000,0000,,My overall mass hasn't\Nchanged.
Dialogue: 0,0:12:46.84,0:12:49.10,Default,,0000,0000,0000,,So it's definitely\Nnot alpha decay.
Dialogue: 0,0:12:49.10,0:12:50.96,Default,,0000,0000,0000,,Alpha decay was, you know,\Nyou're releasing a whole
Dialogue: 0,0:12:50.96,0:12:52.77,Default,,0000,0000,0000,,helium from the nucleus.
Dialogue: 0,0:12:52.77,0:12:54.96,Default,,0000,0000,0000,,So what am I releasing?
Dialogue: 0,0:12:54.96,0:12:57.41,Default,,0000,0000,0000,,I'm kind of releasing one\Npositive charge, or I'm
Dialogue: 0,0:12:57.41,0:12:58.56,Default,,0000,0000,0000,,releasing a positron.
Dialogue: 0,0:12:58.56,0:13:00.94,Default,,0000,0000,0000,,And actually I have this\Nhere in this equation.
Dialogue: 0,0:13:00.94,0:13:04.04,Default,,0000,0000,0000,,This is a positron.
Dialogue: 0,0:13:04.04,0:13:07.14,Default,,0000,0000,0000,,So this type of decay of\N7-beryllium to 7-lithium is
Dialogue: 0,0:13:07.14,0:13:09.76,Default,,0000,0000,0000,,positron emission.
Dialogue: 0,0:13:09.76,0:13:10.83,Default,,0000,0000,0000,,Fair enough.
Dialogue: 0,0:13:10.83,0:13:12.40,Default,,0000,0000,0000,,Now let's look at\Nthe next one.
Dialogue: 0,0:13:12.40,0:13:19.87,Default,,0000,0000,0000,,We have uranium-238 decaying\Nto thorium-234.
Dialogue: 0,0:13:19.87,0:13:25.14,Default,,0000,0000,0000,,And we see that the atomic mass\Nis decreasing by 4, minus
Dialogue: 0,0:13:25.14,0:13:28.91,Default,,0000,0000,0000,,4, and you see that your atomic\Nnumbers decrease, or
Dialogue: 0,0:13:28.91,0:13:31.27,Default,,0000,0000,0000,,your protons are decreasing,\Nby 2.
Dialogue: 0,0:13:31.27,0:13:33.81,Default,,0000,0000,0000,,So you must be releasing,\Nessentially, something that
Dialogue: 0,0:13:33.81,0:13:37.39,Default,,0000,0000,0000,,has an atomic mass of four,\Nand a atomic number
Dialogue: 0,0:13:37.39,0:13:39.68,Default,,0000,0000,0000,,of two, or a helium.
Dialogue: 0,0:13:39.68,0:13:42.21,Default,,0000,0000,0000,,So this is alpha decay.
Dialogue: 0,0:13:42.21,0:13:46.10,Default,,0000,0000,0000,,So this right here is\Nan alpha particle.
Dialogue: 0,0:13:46.10,0:13:48.40,Default,,0000,0000,0000,,And this is an example\Nof alpha decay.
Dialogue: 0,0:13:48.40,0:13:51.11,Default,,0000,0000,0000,,Now you're probably saying, hey\NSal, wait, something weird
Dialogue: 0,0:13:51.11,0:13:51.85,Default,,0000,0000,0000,,is happening here.
Dialogue: 0,0:13:51.85,0:13:56.63,Default,,0000,0000,0000,,Because if I just go from 92\Nprotons to 90 protons, I still
Dialogue: 0,0:13:56.63,0:13:59.43,Default,,0000,0000,0000,,have my 92 electrons out here.
Dialogue: 0,0:13:59.43,0:14:02.75,Default,,0000,0000,0000,,So wouldn't I now have\Na minus 2 charge?
Dialogue: 0,0:14:02.75,0:14:08.27,Default,,0000,0000,0000,,And even better, this helium I'm\Nreleasing, it doesn't have
Dialogue: 0,0:14:08.27,0:14:09.09,Default,,0000,0000,0000,,any electrons with it.
Dialogue: 0,0:14:09.09,0:14:10.39,Default,,0000,0000,0000,,It's just a helium nucleus.
Dialogue: 0,0:14:10.39,0:14:12.70,Default,,0000,0000,0000,,So doesn't that have\Na plus 2 charge?
Dialogue: 0,0:14:12.70,0:14:15.18,Default,,0000,0000,0000,,And if you said that, you would\Nbe absolutely correct.
Dialogue: 0,0:14:15.18,0:14:19.51,Default,,0000,0000,0000,,But the reality is that right\Nwhen this decay happens, this
Dialogue: 0,0:14:19.51,0:14:22.29,Default,,0000,0000,0000,,thorium, it has no reason\Nto hold on to those two
Dialogue: 0,0:14:22.29,0:14:25.05,Default,,0000,0000,0000,,electrons, so those two\Nelectrons disappear and
Dialogue: 0,0:14:25.05,0:14:26.84,Default,,0000,0000,0000,,thorium becomes neutral again.
Dialogue: 0,0:14:26.84,0:14:30.48,Default,,0000,0000,0000,,And this helium, likewise,\Nit is very quick.
Dialogue: 0,0:14:30.48,0:14:33.04,Default,,0000,0000,0000,,It really wants two electrons\Nto get stable, so it's very
Dialogue: 0,0:14:33.04,0:14:36.88,Default,,0000,0000,0000,,quick to grab two electrons out\Nof wherever it's bumping
Dialogue: 0,0:14:36.88,0:14:38.46,Default,,0000,0000,0000,,into, and so that\Nbecomes stable.
Dialogue: 0,0:14:38.46,0:14:40.30,Default,,0000,0000,0000,,So you could write\Nit either way.
Dialogue: 0,0:14:40.30,0:14:42.25,Default,,0000,0000,0000,,Now let's do another one.
Dialogue: 0,0:14:42.25,0:14:43.50,Default,,0000,0000,0000,,So here I have iodine.
Dialogue: 0,0:14:43.50,0:14:45.82,Default,,0000,0000,0000,,
Dialogue: 0,0:14:45.82,0:14:46.67,Default,,0000,0000,0000,,Let's see what's happening.
Dialogue: 0,0:14:46.67,0:14:51.02,Default,,0000,0000,0000,,My mass is not changing.
Dialogue: 0,0:14:51.02,0:14:53.79,Default,,0000,0000,0000,,So I must just have protons\Nturning into neutrons or
Dialogue: 0,0:14:53.79,0:14:55.56,Default,,0000,0000,0000,,neutrons turning into protons.
Dialogue: 0,0:14:55.56,0:14:58.81,Default,,0000,0000,0000,,And I see here that I\Nhave 53 protons, and
Dialogue: 0,0:14:58.81,0:15:00.80,Default,,0000,0000,0000,,now I have 54 protons.
Dialogue: 0,0:15:00.80,0:15:04.06,Default,,0000,0000,0000,,So a neutron must have\Nturned into a proton.
Dialogue: 0,0:15:04.06,0:15:06.83,Default,,0000,0000,0000,,A neutron must have\Ngone to a proton.
Dialogue: 0,0:15:06.83,0:15:09.16,Default,,0000,0000,0000,,And the way that a neutron\Ngoes to a proton is by
Dialogue: 0,0:15:09.16,0:15:11.62,Default,,0000,0000,0000,,releasing an electron.
Dialogue: 0,0:15:11.62,0:15:13.36,Default,,0000,0000,0000,,And we see that in this\Nreaction right here.
Dialogue: 0,0:15:13.36,0:15:16.88,Default,,0000,0000,0000,,An electron has been released.
Dialogue: 0,0:15:16.88,0:15:19.13,Default,,0000,0000,0000,,And so this is beta decay.
Dialogue: 0,0:15:19.13,0:15:20.38,Default,,0000,0000,0000,,This is a beta particle.
Dialogue: 0,0:15:20.38,0:15:25.58,Default,,0000,0000,0000,,
Dialogue: 0,0:15:25.58,0:15:26.75,Default,,0000,0000,0000,,And that same logic holds.
Dialogue: 0,0:15:26.75,0:15:32.78,Default,,0000,0000,0000,,You're like, hey wait, I just\Nwent from 53 to 54 protons.
Dialogue: 0,0:15:32.78,0:15:34.44,Default,,0000,0000,0000,,Now that I have this extra\Nproton, won't I have a
Dialogue: 0,0:15:34.44,0:15:35.75,Default,,0000,0000,0000,,positive charge here?
Dialogue: 0,0:15:35.75,0:15:36.48,Default,,0000,0000,0000,,Well you would.
Dialogue: 0,0:15:36.48,0:15:40.81,Default,,0000,0000,0000,,But very quickly this might--\Nprobably won't get these exact
Dialogue: 0,0:15:40.81,0:15:42.74,Default,,0000,0000,0000,,electrons, there's so many\Nelectrons running around-- but
Dialogue: 0,0:15:42.74,0:15:45.95,Default,,0000,0000,0000,,it'll grab some electrons from\Nsome place to get stable, and
Dialogue: 0,0:15:45.95,0:15:47.08,Default,,0000,0000,0000,,then it'll be stable again.
Dialogue: 0,0:15:47.08,0:15:48.89,Default,,0000,0000,0000,,But you're completely right in\Nthinking, hey, wouldn't it be
Dialogue: 0,0:15:48.89,0:15:51.69,Default,,0000,0000,0000,,an ion for some small\Namount of time?
Dialogue: 0,0:15:51.69,0:15:52.90,Default,,0000,0000,0000,,Now let's do one more.
Dialogue: 0,0:15:52.90,0:15:57.21,Default,,0000,0000,0000,,So we have to 222-radon-- it\Nhas atomic number of 86--
Dialogue: 0,0:15:57.21,0:16:01.72,Default,,0000,0000,0000,,going to 218-polonium, with\Natomic number of 84.
Dialogue: 0,0:16:01.72,0:16:03.54,Default,,0000,0000,0000,,And this actually is an\Ninteresting aside.
Dialogue: 0,0:16:03.54,0:16:08.38,Default,,0000,0000,0000,,Polonium is named after Poland,\Nbecause Marie Curie,
Dialogue: 0,0:16:08.38,0:16:11.22,Default,,0000,0000,0000,,she-- At the time Poland, this\Nwas at the turn of the last
Dialogue: 0,0:16:11.22,0:16:15.12,Default,,0000,0000,0000,,century, around the end of the\N1800's, Poland didn't exist as
Dialogue: 0,0:16:15.12,0:16:15.91,Default,,0000,0000,0000,,a separate country.
Dialogue: 0,0:16:15.91,0:16:19.54,Default,,0000,0000,0000,,It was split between Prussia,\NRussia, and Austria.
Dialogue: 0,0:16:19.54,0:16:21.59,Default,,0000,0000,0000,,And they really wanted let\Npeople know that, hey, you
Dialogue: 0,0:16:21.59,0:16:24.00,Default,,0000,0000,0000,,know, we think we're\None people.
Dialogue: 0,0:16:24.00,0:16:27.17,Default,,0000,0000,0000,,So they discovered that when,\Nyou know, radon decayed it
Dialogue: 0,0:16:27.17,0:16:27.73,Default,,0000,0000,0000,,formed this element.
Dialogue: 0,0:16:27.73,0:16:31.43,Default,,0000,0000,0000,,And they named it after their\Nmotherland, after Poland.
Dialogue: 0,0:16:31.43,0:16:33.88,Default,,0000,0000,0000,,It's the privileges of\Ndiscovering new elements.
Dialogue: 0,0:16:33.88,0:16:35.09,Default,,0000,0000,0000,,But anyway, back\Nto the problem.
Dialogue: 0,0:16:35.09,0:16:35.93,Default,,0000,0000,0000,,So what happened?
Dialogue: 0,0:16:35.93,0:16:39.21,Default,,0000,0000,0000,,Our atomic mass went\Ndown by four.
Dialogue: 0,0:16:39.21,0:16:41.43,Default,,0000,0000,0000,,Our atomic number went\Ndown by two.
Dialogue: 0,0:16:41.43,0:16:44.58,Default,,0000,0000,0000,,Once again, we must have\Nreleased a helium particle.
Dialogue: 0,0:16:44.58,0:16:47.07,Default,,0000,0000,0000,,A helium nucleus, something\Nthat has an atomic mass of
Dialogue: 0,0:16:47.07,0:16:51.16,Default,,0000,0000,0000,,four, and an atomic\Nnumber of two.
Dialogue: 0,0:16:51.16,0:16:52.10,Default,,0000,0000,0000,,And so there we are.
Dialogue: 0,0:16:52.10,0:16:55.95,Default,,0000,0000,0000,,So this is alpha decay.
Dialogue: 0,0:16:55.95,0:16:57.81,Default,,0000,0000,0000,,We could write this as\Na helium nucleus.
Dialogue: 0,0:16:57.81,0:16:59.14,Default,,0000,0000,0000,,So it has no electrons.
Dialogue: 0,0:16:59.14,0:17:00.82,Default,,0000,0000,0000,,We could even say immediately\Nthat this would have a
Dialogue: 0,0:17:00.82,0:17:02.99,Default,,0000,0000,0000,,negative charge, but\Nthen it loses