Full transcript
0:00eventually the electron jumps back down
0:01just like this image shows in fact this
0:03image shows it kind of nicely where
0:05photon comes in it absorbs it jumps to a
0:08higher energy level later on it falls
0:11back down and spits out a photon of
0:14light exactly the amount of energy from
0:17here so this maybe is taking 1.5 joules
0:21to jump up that photon is absorbed and
0:23then when it jumps back down it spits
0:26out a photon and you can see it's gonna
0:29be in a random direction in this case
0:30the random Direction happens to be the
0:32back the same way but it's spitting back
0:34out a photon later on in a random
0:38direction now it's also worth mentioning
0:42and don't get confused by these Balmer
0:45series Lyman series I'm not gonna ask
0:47you about that but what can happen is
0:49that electron could jump remember to a
0:51higher maybe doesn't jump from this
0:53orbit to this one maybe the electron
0:55jumps all the way from here to there
0:58well when it falls back down that
1:03electron might go from here all the way
1:06back to there or it might cascade down
1:08in parts where it jumps to this one then
1:11this one then this one if it jumps down
1:13in layers each time it will spit out a
1:16photon of exactly the amount of energy
1:18from this line to this line so it might
1:21absorb one photon of light and then on
1:24the way back spit out a few different
1:26ones so again the main idea though is
1:30this absorbing the exact right energy to
1:33jump to our energy level and only that
1:36exact amount of energy any other energy
1:38would pass right on by so why does this
1:43have to do with spectra
1:44well everything remember we have this
1:49continuous source giving off or this
1:53source giving off continued spectrum and
1:55that's what we normally expect to see
1:56but it's that same source goes through a
2:00cloud of gas we end up with this weird
2:03absorption spectrum well what's
2:05happening the elements within here some
2:09of those elements their electrons are
2:12absorbing the exact
2:13right amounts of energy and jumping up
2:17well remember energy just means
2:20frequency certain frequencies of light
2:24are being absorbed certain lines are
2:27being absorbed so the light passing
2:31through here some of the elements are
2:33absorbing those lines and because it has
2:37different levels it can jump up to we
2:39get the different lines being absorbed
2:41but it all depends on that specific
2:43element within this cloud of gas it will
2:46absorb only those energies it can all
2:49the others all these other lines are
2:51passing tour undisturbed only very
2:54certain ones where the electron can
2:56absorb that photon that packet of energy
2:58that frequency of light those can absorb
3:01and disappear and are now a black
3:03missing line but that same cloud of gas
3:08later on will spit out light and now
3:11some people are immediately I think well
3:13if it's spitting that same photon of
3:15energy back out why isn't it filling in
3:17because it spits it out in a random
3:20direction most likely not in the same
3:22direction and Plus this probably passed
3:24by even if it is only a fraction of a
3:26second later it spits it out well it's
3:28probably impossible it's already passed
3:29like it's mostly just that it's in a
3:31random direction so if we're looking
3:34over here that same gas cloud will spit
3:37out light and again since the and that's
3:41why if we heat up this gas cloud giving
3:43it energy giving the electrons energy to
3:46jump to a higher energy level when it
3:48starts to emit light when those
3:50electrons fall back down to a lower
3:52energy level they will spit out only set
3:54energies only set wavelengths and that's
3:57why we're going to see this spectrum of
4:01lines right here that's the exact same
4:03lines that were absorbed so it all goes
4:07together the electrons only absorb very
4:10set energies and that's why we can
4:13determine what this gas cloud is made of
4:15because we know from the lab certain
4:18lines represent certain elements one
4:25final thing worth mentioning
4:26now we kind of left out is that if those
4:30electrons were given enough energy I
4:32mean we saw that if they give an energy
4:34they jump to a higher energy level great
4:36but they were given enough energy that
4:40electron can actually get removed from
4:42that atom it can jump past all of the
4:46allowed energy levels and no longer be
4:48part of that atom at that point that
4:50atom now has an overall positive charge
4:53because it's lost one of its negative
4:55charges so it gets a positive charge and
4:57the thing is now this process called
5:01ionization the removal of an electron is
5:03ionization and so this atom is now
5:06called ionized as a positive charge is
5:08ionized because it's missing an electron
5:10and actually this ionized form of the
5:13atom would have its own different energy
5:16levels so even if it's an ionized form
5:18of our atom then we can still determine
5:22what it is within the gas cloud so and
5:25we can do further ionization depending
5:27on the gas we can move more electrons
5:29overtime from that atom as well and that
5:32just requires progressively more and
5:34more energy to knock that electron away
5:37from the element and it is possible for
5:40an atom to recapture an electron later
5:43on as well