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thank you this today we're gonna talk
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about electron configurations looking
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true electron configurations are so
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important because remember that
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essentially all the chemistry that goes
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on is a result of electrons either being
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transferred or being shared everything
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in chemistry essentially has something
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to do with electrons with a couple of
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exceptions chemistry essentially is the
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study of electrons and where they're at
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and where they're going to and how
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things are coming together and and the
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reason that they're trying to come
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together it has everything to do with
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electron configurations the reason that
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chemical reactions of any kind happened
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the reason that chemical bonds happen is
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because of electron configurations
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everything here is about electron
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configurations at how are the electrons
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arranged so for instance what I say that
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everything revolves around electron
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configurations everything every reaction
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essentially is trying to get to this
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column as far as its electron
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configurations everything wants what we
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call a ng EC or a noble gas electron
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configuration typically speaking that
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means eight valence electrons helium
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hydrogen those are a couple of
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exceptions but but basically that's why
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everything happens covalent bonds ionic
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bonds they're gonna happen in order to
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get to an electron configuration that is
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the same as that of a noble gas and why
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is that well because they're called
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noble gases because essentially they
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don't react with anything else because
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they already have the electron
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configuration that they really really
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need so that's going to lead us into
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electron configurations and we're gonna
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talk about the three rules of electron
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configurations but first off I want you
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to take out a periodic table okay as
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you're taking notes if you got it up on
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another screen or another device or
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whatever if you get a paper copy have an
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electron configuration or having a
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periodic table out in front of you as
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we're going through this so that you can
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see what we're talking about I think
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things will make a whole heck of a lot
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more sense if that's the case so before
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we dive directly into the rules of for
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electron configurations I want to talk a
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little bit about the periodic table and
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how it relates so I'm going to label
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each of these if you remember in our
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last video we talked about different
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types of orbitals
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so we said that we had s or girls that
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look like sphere and we had P orbitals
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that look sort of like an infinity sign
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or sort of like a little dumbbell
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structure and then we had D and F
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orbitals and they really started to look
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really weird
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well that s P D F each one of those
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things corresponds not just to an
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orbital and a that goes into our
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electron configuration so we're going to
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talk about here in a second but
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specifically refers to a part of the
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periodic table that goes right along
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with it and so each of these levels here
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in what I'm doing corresponds to
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specific orbitals so you'll see here
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that everything I'm writing in this
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little green region that everything I'm
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writing in the green region is an S and
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that means that everything in these
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first two columns of the periodic table
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ends in S orbitals their outermost
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orbital is that of the s and that's that
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spherical one to remember that we talked
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about okay and so you should already
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sort of be getting in your head that hey
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does that apply to these other areas of
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the periodic table and indeed in fact it
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does and so if we come over here we've
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got two P all the way across and then
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we've got three P 4 P 5 P 6 P and of
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recent interest to us is that we've sort
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of filled in the 7 P part of the
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periodic table here really recently in
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fact with our good friend tennis scene
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in there as well so we've got the
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s-block of the periodic table we have
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the p block of the periodic table and
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you can sort of already from knowing
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what you know from the last video
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figured out that there's a D and an F
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block as well and so in this region is
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the 3d and you'll notice I didn't draw
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all the individual elements there I
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didn't really feel like that was
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particularly necessary at this point
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because you've got a periodic table in
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front of you that you're gonna use to
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follow along as we start to do the
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actual electron configurations so the
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middle region the valley part of the
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periodic table there that is the D block
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and I'll come back to why the numbers
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seem a little weird to you here just
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and then down here at the bottom is the
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F block with the lanthanides and
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actinides okay and of course we remember
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how many blocks are here there are ten
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divisions here there 14 down here that's
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gonna be really important to stop and
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pause and look at your periodic table
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and make sure that you see this 10 and
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the 14 once in a while you'll see 15
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down here and we'll talk a little bit
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more why that is as we go on what what
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you probably noticed immediately is that
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what about that helium up there you
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didn't really label that helium and
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hydrogen since they're so small they
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sort of have some exception capabilities
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but helium doesn't like to react it's a
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noble gas in that case but it actually
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only contains the 1s okay now what you
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will also notice is that as you go down
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each period remember that rows are
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period periods in the periodic table and
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so as you go down each one of them you
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are adding another energy level if we
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were to draw that in terms of the Bohr
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model we would have one little circle
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and then we would have a second one and
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then a third one and so on and so forth
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until we had seven energy levels there
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associated with that so we can see that
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energy levels are going to tie in with
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our orbitals now we're not going to go
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too deep into this but all of these
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things correspond to something called
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quantum numbers quantum numbers
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essentially give us an a way to uniquely
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identify each electron within an atom
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and the first two quantum numbers are
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the energy level so the 1 to 1 you know
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1 through 7 here and then the second
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quantum number corresponds to the letter
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whether it's s P D or F and again we're
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not gonna worry too much about that
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right now but you need to know that
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there's a rationale and a reason behind
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what each of those things are and so we
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can see that we're gonna fill things up
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in this way we know you guys already
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know from middle school that if you drew
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a nucleus and then you had one or or
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Baton dat one of Bohr's models around it
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then you would have one energy level
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then you could put a second one on top
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of that and you would know that you feel
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from you putting your electrons from
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closest to the nucleus on out and so if
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you were
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drawing a boar model you've got your
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nucleus here okay
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and then you've got one two let's say
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three energy levels and if we were
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adding electrons on to that let's say
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that we were doing your middle school
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interpretation of sodium which is right
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here and sodium has 11 for its atomic
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number that atomic number remembers also
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its number of electrons if it's not an
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ion and so you guys probably in middle
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school filled these things up and you
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said hey I can put two in the first
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level and then I can put eight in the
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second level okay and then we would put
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the extra one out there on the third
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level and that's how you did energy
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levels in middle school well what we're
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going to do today is very similar to
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that but there's some rules that say hey
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it's not just quite as easy as that and
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it also matters not just like what
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energy level they're at but what really
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matters is what warbles they're in as
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well and that's going to lead us into
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the idea of valence electrons and all of
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that stuff a little bit later okay so
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energy levels sdp F blocks or I would
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prefer if you said s P D F blocks you'll
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notice that there's some weird
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discrepancies here so like this is
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energy level four okay so for s for P
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but in the middle there's this weird 3d
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here and this is what makes electron
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configurations a little bit complicated
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because there are those exceptions there
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in that this is energy level four but
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what's gonna fill in between parts of
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four is parts of three you'll notice
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that all of the DS are exactly one below
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where they would be if they were in the
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s and P level and one other quick thing
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that I want to make sure that you note
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is that remember that your F block
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actually fits in like right here okay
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and if you look at your periodic tables
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or if you've looked at the longer
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expanded version you know that all of
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this slides in here and then we would
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get this big long giant periodic table
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so you'll notice then if we put that in
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that the FS would for F and 5f would go
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here and that would be two levels below
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the s and the P there there's a lot of
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reasons behind that there's what we call
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the penetration effect and all of those
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things they're going to set up
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some weirdnesses for where the electrons
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are all more than we really need to know
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in chem 1 what we really need to know in
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chem 1 is how can I take an element okay
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know how many electrons it has and then
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be able to arrange an electron
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configuration for that how can I write
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this out in such a way that I can get
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all of my electrons in the right place
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because I need to know that to know how
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things react really well so let's talk a
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little bit about that
