Lecture 10. Polarizing Power and Covalent Character
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Lecture 10. Polarizing Power and Covalent Character

Title of Series  
Part Number 
10

Number of Parts 
23

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CC Attribution  ShareAlike 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal and noncommercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor and the work or content is shared also in adapted form only under the conditions of this license. 
DOI  
Publisher 
University of California Irvine (UCI)

Release Date 
2013

Language 
English

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Subject Area  
Abstract 
Chem 1A is the first quarter of General Chemistry and covers the following topics: atomic structure; general properties of the elements; covalent, ionic, and metallic bonding; intermolecular forces; mass relationships. Index of Topics: 0:00:24 Polarizing Power and Covalent Character 0:02:36 Bond Strength and Lengths 0:03:38 Molecular Shape and Structure 0:05:29 VSEPR 0:10:40 Steric Number 2 0:12:20 Steric Number 3 0:16:19 Steric Number 4 0:21:44 Steric Number 5 0:32:31 Steric Number 6 0:38:42 Geometry Examples

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so did 2 quick things to finish up from Chapter 2 unjust to quake topics that we need to know before you can really move on to the background info on and then go on to the sort of the year the pure workshop that we had planned
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out so hopefully Albright your into thick so we have I think called polarizing power and Paula I implore his ability to users certain 2 opposite concepts in a way so that more electrons that you have the further they are from nuclear straight so that kind that give us an idea of Samara transmit as going down the periodic table and there's also has to do with polarize ability and polarizing power so if you have a very far electrons then nuclear isn't going to be able to really affect things that are going on far away from it so if 2 things are bonded to each other in Newry telling and ad on the air that has very far off electrons is not being able to affect the other nuclear says electrons very much and that comes in the deal polarizing power the ability of 1 Adam to polarize another now conversely that that is something have a lot of electrons it's very polarized so something a lot of electrons this complete control over its electrons a it's trying to sort of balance all of these elections are a long ways away from inchhigh control that so some of the Adam comes around that can move around to push that electron density around more electrons the more it can be pushed around the mall more polarized boys Is it Carey leaving control all electrons it's not going to be able to push around other arms of the eyes electrons so it's not going to have very much polarizing power now the opposite to that then is this something is small To something is very small something like a L 3 plus I knew very highly positively charged small nuclei are small and that will push around other Adams electrons pretty easily because they have a lot of polarizing power it doesn't have a very large electron clouds it's nuclei can be felt a lot it has a high affected nuclear charge and those have a lot of polarizing power to move bank with a lot of electrons is very polarized the ball something that small without wearing the electrons have a lot of polarizing power and 1 more small topic that we need to sort of talk about Selene having a background knowledge when we talk about all sorts of things from now on is the difference in correlation between bond strengths in bond lengths so something like this single bond is going to be weaker and longer than something like a triple by so if we compare the different types of carbon bonds a single bond is going to be the longest and then double 1 in the trouble on a course that we talked residence you know that we can have things are in between that to right we can have a bond orders of like 1 in the 3rd a 1 and a half because of the way that Lewis structures work solely because of that we can have in between things so that's 1 of the ways that we can sort of tell what kind of bonds were looking at we can measure the length of we can say Well that a single binary double Bondra triple travelogue based on how long it where trouble on a single line 1 so this is sort good to have in mind as a talking about different bonds in how they relate to each other so this vision capital up to now I need to go onto molecular shape and structure Chapter 3 so now we get to go ahead and we get to learn how bonds in long pairs are going to affect the geometry still so far and has been drying them out a lot of my conjure up the shape that they look like Louis structures don't accurately represent that Lewis structures that I will not going to tell you what shape they are you don't have a job was in the shape that they are in fact your homework you probably saw that purposely they were drawn in ways that that maybe didn't show you the shape so you have to get from Europe where you look at how these geometries that work with what we learned last class about the polarities of bonds to get us that whether it is or is the polar molecules so we went through we looked at all of our Lewis structures we set up in the Paula bonds but I was very careful to make sure that you realizing where the signing of the molecules Paula and right isn't a candidate yet so after today will be able to go through and we to say OK this molecules polar this molecule is a and Y rather than just talking about the bonds and there are going to go into this concept of 2 different means Dureza bonding to from where they can look at how molecules bond and how they work together still talk of valence bond theory a hybridization which is used a lot in the organic chemistry section of and it's very it's very quick and easy once you know have the key word there being wants you know it it works really well too but it doesn't break down sometimes it's not a it's not 100 per cent predicted on and 100 per cent effective but it is very good at explaining things but there are some problems with it and so molecular orbital theory fixes some that but create a whole new problems being sued complicated and requiring computers and adding a wave functions all those we functions you love so much harder back and things of that sort that women want to talk about it so let's start with the obvious CPR theory so before we start filling out your worksheet and going through the workshop needle couple definitions so the DNA hearing loss and be going thinking added doing all these geometries is that we have these electrons they're all negatively charged they'll 1 in injury time right they'll have the same charge they're all negative charge the inner repel each other they wanna be far away from each other so the idea is how can we get this as far apart from each other as possible now in addition to this electron pairs artificial more repulsion than a bond so if you have electron the bonds they still don't want near each other there a little bit more willing to be near each other than something that's just a lone pair and when we got into this switching double and single trouble belonged as exactly the same thing for the job and geometrical purposes so this is sort of what we're going to keep the mind as a tiny species molecules out in 3 states now the true definition that we need to go through talk about stare number in coordination so stare number is if we take it 2 1 out with all of these cases we're looking at 1 Adam and we say how many bombs doesn't have it in this case I really should be saying how many bonded Adams either that's important distinction you count the number of about the bonded to a single and double bonds at its and double and triple bonds treated the exact same way single and income of the lone pairs they have some coronation in this is just the bonded out so you'll notice the difference here this has bonded Adams and the electron pairs this just has the bonded about Adams in Dublin from among the treated as 1 in this case so if we look back at and once they got its Accord nations Derek number we say Well how many things are bonded to it 1 2 3 How many long Paris half 1 says coordination number the new 1 2 3 it's staring numbers than anyone to 3 4 1 this 1 now we have 5 bonded out and we had no lone pairs so you're saying loneparent Florian remember we're just talking about the phosphorus here so it would typically when we talk about stared memory coronation Amber were only going to be talking about having the bonded to more than 1 thing so that's going to feature a woman talking about the geometries and when we start talking about hybridization were focused on the part of the bonded to more than 1 thing so we're just focused on the central the fastest so 5 times no long cares said stare numbers 5 as coordination now if we had this 1 now we see that we have 5 bonded out and 1 lone pairs to or stare at number 6 because if I bonded Adams Wilmont Perry calls 6 accord nation numbers just 5 0 2 loss at definitions before it month so we had a letter from damaging have molecular geometry now not really given no hard figures are on the side that's fine decided on actions class you will but they are going to be different so we go back and look at the developments that we just talked about and we will get there 1 geometry the electron geometry is going the acting as evident from these electrons these electrons are a part of it In so something like this would be touches the girl because there's 4 things including the electrons but molecular geometry will be different in the world will not have not been may be class but of molecular geometry just looks as if you can only see the hydrogen and we can't see the electron pairs now they are trying the affecting the molecular geometry of sending us a lot while a case of the electron geometry it has to do with the electrons the molecular geometry only has to do with what bonded to a decision not necessarily true kind of share the molecular geometry is looking after from Paris specifically that won't fare as lone pair effects where the molecules to be in so it's still affected by Yukon newly seperate them so if we look at this time so there is no apparent and Primestar molecular electron geometry turned out to be the same so whenever you don't have a lone
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pairs on in central and they're going to be the same because there are no long periods that are affected it if we look at something like that back to the same idea where now we have a geometry is if we were including his electrons if it if we could see these electrons and 1 of which we can't were suddenly these electrons are really there anyway but they're still going to be affected the geometry still be affected by the fact that the lone pair is but other Sinaloa the easiest way to go about doing this because it's impossible to see you in 2 D is to actually build the last year to bring to fixing came here here model car model capitalize Haydn's 1st year here you go so we want the building along with me I going about it so we have a worksheet that government can get and so he engulfing do this work will start with the lowest stock number which is to begin only really talking about things are bonded to more than 1 out of the staring at you and we're going work our way up to stare at number 6 in each time we go through organist take take away when the atoms in Poland has to go another Adam along parallel in see how we can build all these up and how they look very similar and for all of these sorts of little animation you can come here and so that you can see them all of them .period through my slides so firstact number 2 we too want find a way to space hour to Adams is much as possible so if we want to take 2 things and we want a space enough as far apart as you can the way to do that is 180 despite not exactly like this the was far apart from each other as possible so as we look at this we think I'm looking to see what we think the geometry of the very 1st of all the electron geometry and molecular geometry are need to be the same because there are no longer has entered in a straight line straight line right to recall that linear they're the same because there is there's no 1 cares to factor in there and 1 of the bonding well from here to here it's going 180 degrees and so does a linear molecule so if you have a document to it's just that anywhere in solar looks like certainly on new undisturbed number 3 said that we have to think OK easier geometry mines where thank go to space all 3 of these out completely equally remember we have threedimensional space work with here so he can face everywhere now it turns out both for certain number to answer a number 3 they artists on a plane so if you try spaces out as much as possible you get there this is a sort of geometry a working now if both are staring number Air Force turnovers 3 new no lone pairs are coordination numbers also and so in that case the reluctant molecular geometry candidacy but I have to sign with the cultists well look at the shape of that needs 3 points set triangle and it all Indian 1 plane right it's available aggressive all the upanddown plane so it's trailed playing so we're eternal cleaner geometry now people they will do I have to memorize all this in and there's a level of memorization to it but it doesn't make sense if you can see if you can see this you can think of how the names working you can it makes a lot easier to memorize the names if you're just taking this table once we have filled out in the 9th memorizing and that's a little rough and kind of useless sold memorize what they look like any kind of related names to them now from but I think those old and you don't have to 1 that's a little tricky if you don't memorize that I and II to suggest just memorizing it but for the rest if you know what they look like it's not really memorization for instance this 1 if you know that it's 3 all on a plane you know what it is all the way around right that's 360 this full circle all around so because of that you know that each 1 of these is the 3rd of the seats 1 20 so you only have to memorize facts so that the number 3 and Perez but what if we have a lone pair What I take this off and I say Well this is now there's still something here but in the long parent it's not an adult so if we do that we have some examples here down down there for you for each 1 seeking Tennessee newsreel molecules too so they do this now we still have this shape it's not like this is gonna come in space out here because that lone pairs still still there In this long hair now remember on the very 1st slide and I talked about a string theory they said lone pairs take up more room that is the lone pairs and pushing down it's going to be taking these in that it just pushing down a little bit more now estimates that the atoms of were both aware of it so if we do that we can now decide with the shape of this molecule is so if you look at the shape of this molecule you can call it bed right it's not linear it's bent is kind of squished over so are electron geometry stays the same because the electron geometry still seeing this Monteria the slogan pair here on molecular geometry and the other hand the new bad because this was it's not linear anymore it's better now closer bond angles so there but angle it used to be 120 but in this case is not going to be quite 120 anymore because the long Paris taking up more room in squishing it down its question of bonding go said it's more like this and so what you're going to end up having is less than 120 it's not going be quite 120 anymore so there are a few examples about 1 and now hold that takes care of certain 3 we did another 1 were back to this concept of only being bonded to 1 thing in which case you don't really talk about geometries so now the understand number 4 story building something that looks like tests said that the rule that was a little bit tougher going to see beginning really have to think threedimensional only to see this 1 easily so if we don't do this the waiter Spacey's out completely in making the easiest way to think about it is to think about putting us out of the middle of a box and then drawing from the center of the box out to all 4 quarters and so we have the shape so we have an added incentive box John out of work and so we have attaches to address right so the shape of this whole thing that this shape that it would that it would be making if we made this into a threedimensional thing with the attaches the dress so the molecular geometry of the sentence called Tetris he drawls so that the molecular geometry now 3rd the electron geometry season now because this is also no longer parents it's stare number in its molecular G it's starting among coordination number the same banning this molecular geometry is also going to be tough for perhaps not a barnacle part in this 1 and this 1 is not really super obvious unless you happen to be really good geometry this is 1 they may just want to have to memorize so the bond angle here is 109 . 5 it's not 90 right because it's not that we're taking 316 dividing by 4 we're taking 316 all the dimensions and dividing by 4 so it's not quite as obvious as the other ones so this 1 is 1 that you may just want memorize on some models but soon now we can take you wouldn't take 1 of those away so we can prolong parallel if we do that this geometry now if you look great well 1st electronic monitoring electron Yamashita don't change a from geometry is still seen as the shape so electron itself the molecular geometry changes now trade can now are just looking at the shape of the molecules are the Adams seized so if we look at this don't here we have a triangle the street they form a triangle now it's not all on 1 plane acknowledged in a pyramid shape so it's going to be eternal promise the triangle based in a pyramid now if we look at our bond angles we still ,comma 109 . 5 about but now we have this lone pair here squishing everything all over so it's not quite 109 . 5 it's less than 109 . 5 In you don't really have to worry about exactly what those numbers are just know that is less than
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1 . 5 I exams you call 125 new not right for this it's gotta be left the expect you know how much last but definitely know that it's fast other Sersen ,comma examples from now let's keep going now we can actually take off another way we depend another long pair it was in the best shape so and now we have the shape we have long Perez on there that we can see in this sort of drawing visitors near Staples emboldened Vannatter ever show the lone pairs and if you do that are electron mystery still tougher but we're back to a certain band structure right In this adventure is definitely still called backed by notice it's not the same as the the other band that we talked about it's not the same as the band where we took the trio playing here because the state number 3 so we just took away 1 because didn't back from you look back your notes in the Sullivan had a bonding over 120 that's not the case said because this comes from a tough procedural original electron geometry bond angles 109 . 5 so it's still going to need about 109 . 5 but it's going to be less than that furthermore is not only the loss of 1 . 5 but it's going to be less than this too because here we only have 1 set of lone pairs pushing down here we have 2 sets of 1 Paris pushing up so we don't need to worry about which number that is but you do need to know that it's less than that so I could give you unexamined Secondary 1 in each of these Intel rank bond angles and you know that this was going to be the biggest and then this 1 and this 1 I can also be tricky and Guinea something like as 1 of these you know that that's going to be bigger than all of these because this 1 is based on 120 but this 1 is based on 109 . 5 and then moving down so that takes us through that arm section of your cable so that it assumes Stirton before and now we need to do stare number 5 and so this 1 out I studying complicated the easiest way to go about building a slump instead think about 1st putting them directly across from each other so the 1st thing you do this puts to Adams directly across from each other In that sense of 2 of em now comes the next 3 goal all along the center it equally spaced intervals this temperament so we get the shit these 2 directly across from each other in a sort of linear fashion and we have these 3 along the middle and basically kind of that we had a treadmill preparatory on planar set to have both of these combined together hence says that panel 3 dimensions of taken minor and too much so if we look at this now we look at the shape of that so remember that they send live a triangle in if we just ignore this for a minute news take us away and we look at the shape that that makes we could say Well that's a triangle in sort of a pyramidshaped right triangles are your on Friday will knowledge that the sum back ensued the summit site no it's likely double that so we have a triangle a pyramid shape up here and we flipped it only made a triangle of chairmanship appear to us to obtain so trying educational parental trail from about this too about the tribunal by parental is the name of the sort so we have 3 about animals and then because there's no loan Perez yet we haven't gotten there yet we have triggered by parental molecular geometry to now it'll get by animals and this isn't quite as simple as the other 1 because we had 2 different sets of this sort this 1 are really the same geometrically Harry they're not actually identical so if we look at this binding all over so afraid we'll get this bond angle here to hear that's a 90 degree angle we know that this is 1 AT and so that's being Splain have set a 90 degree angle now if you look at this 1 from here to here all the way around its 360 it is being splintered the Secretary of playing so this angle is 120 this angle is 90 so they're actually have to list both of them now continuing on the patent let's take 1 of these away In turn it into a I'm In turn into a lone pair now although there's some extra complications when it took only 1 from the traditional trampling there are 21 from the tougher fuel it didn't really matter which 1 we took geometrically were all completely equal although bonding over the same it didn't matter where I put it and I put it in in 1 place it was the same as GE's rotating around and playing in a different place that's not true hearing more and now we have different bond angles now we have a 90 degree and we have a 120 so we what put it where has 90 degrees to play was or 120 degrees platelets so this desire and now we have to decide which 1 takes up more room to the bond take up more room for the long pair take up more sure about take some very longhaired more room so we need is a lone pairs much room to maneuver as possible so if we want to give along parallel room Oregon again at 90 degrees to play with reading of 120 degrees .period that lying about 120 suppliers so we take it off from here now we also have this case where because this is a situation where these arms are not the same we need have a way to designate the difference between that we need to nomenclature here we need to know what we can call this as opposed to what we can call this and so if you think this is going on below exactly this that water which fashion I handholding holding area now what runs down the center of a and access to these are axial ball the funds on our axial then let runs around the side around the center of a the equator Salinas where pictorial to axial we have Ecuador so you always want take away and prolonged pair on an equatorial position you wanna give 120 degrees on each side to play with not just 90 so now we have the shape the shapes are a little bit easier to see if you flip on sideways so the foot the sideways and we look at how it looks like we can think about is like 1 of those new teeter totter things that we saw but cheered higher is not the proper terminology here the money the other word for it which is the so this is this molecular geometry the indices now Our bond angles seen as before they're just going to be the 1 20 in 190 except now this lone pairs pushing everything a little bit and so the thing was going to be a little bit less than 120 this thing was going to be a little bit less than 1 area in Boston 98 so we're talking about the single here right from this is going to be less than 120 in the careful derided the sway of a lot of time students already 90 in last signed which doesn't work right Yukon is careful about like that saying that 90 is less than the angle this angle is less than 90 cemetery where they like so the couple examples on all of these examples I'm putting up here that's just sort of Fourier involves can actually have some practice trying them so you should really go home and take all the different examples I've put out a news amid Lewis structure practice go through Lewis structures make sure Jolyn and make sure you can see the geometries and it's been sort of like just putting a a blank piles of practice and then using them to know what they are in matching up to slide into the bottom right but it so now we have to take away another 1 pair there so if we do that we have to decide where take from and and then we get this choice of a little less than 120 were get this choice of a little less than 90 and so we're gonna wanna take away which 1 the other 1 is greater than 120 Virginia less than 120 bands that means that we're going to have this shape and so again to name must look for but
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side Switzerland is now understand so fruitful but uninspired at the tea break the chip like a TV and so it's too so electron Dimitri seamers before molecular geometry Tshaped enough however bond angles so before adjusting glory here was 90 and then it got to be less than 90 and now it's going to be even less than 90 we are even more less than 98 at the it's an even smaller so now it's going to be a little bit more tilted and solely about color shape to it said 30 market now just like before I can ask you to ring the Callaway a crossed and I can ask you to go through and say Well if I gave you 1 from here and 1 from here 1 from here their wrinkles in order bonding anyone be able to say what this is going to be the largest and this 1 and then this 1 so now we have our last winter in this steric numbered so we take away a Tshaped reality shaped and now it is I will taking away from here were we have about 120 between this and the next lone pair or here where we had 90 far less than 90 3 take again from Equatorial position so now we have this shape so still channel by parental now we have linear the linear shape again now again notice of this isn't quite the exact same linear is the previously near that we wouldn't we have only a year before we had to start number 2 officers in that case right now Amsterdammer 5 we have 3 long pairs around here so even tho it's called the same thing and bomb will look barnacles here 2nd it's not you still on a single a slightly different things right because the electron geometries different this is the trio by primal electron geometry with the other electron geometry with stirring worked who was just 1 year as well so are binding goal here so what we think what the binding of produced almost 120 the it's in his 19 well that's not really a binding only more because there's no bond here we can have this 1 20 here anymore either because there's no bonds here to compare to SOS really just 180 now the question is a little less than 180 because all of these were less than nothing to the left and the right of all the pushing the same so we have a long pair here long pair here lone pair here and there all pushing equally on all of these Adams and so because of that it's just 1 so example of this would be like I 3 minus a X C F 2 other Sonora last set of staring numbers most difficult to go through and do with tedious because they seem to be having some problems with their phone line and Beijing just switched doing it with the stick cells if we move offshore stared number 5 the 6 times during the 6 the where these get spaced out they're are all equally like best they're all equally spaced you can think of 1 basically is that a different the 3 different axes like a Cartesian referee xyz so they're directly across from each other so a now we're about all of these being geometrically equal when you know that is there is no real difference between the spot in the spot right now if I just want to rotate it like this this would be exactly the same I didn't change anything so that's what I mean by that all being seen so we don't where about SEC which on axial thing that we did with the trio by so this is going to be called he drove now that I'm is not super obvious so socalled I think we have bonded 1st of all I stared 6 6 things bonded and yet we call a doctor he dropped so why is that while the name like it is wider than he dropped so keep in mind were looking over the shape of the threedimensional shape at this makes so if you look at this threedimensional shape when you actually have it 8 cited figures you have assigned here side sides here site here if I got the pyramid with a square base it's like a square pyramid on both top and bottom answers 8 sides and so because there is 8 faces to the shape is called he drove not that high taxes the draw anything like that it's talking about the shape of the molecules or the shape of the I think rather than how many things are bonded to it I just happened with the way that the tab for refusal a sign up that both it formed the Tejeda in Anaheim for things so the little bit of her electronic molecular geometry the same Paris and we have a bond angle of 90 so the 90 this is another 1 don't don't worry about memorizing lists you can you can look at it if you know what the molecule looks like there's no memorization here you know that each of these are like you're different xyz access rights Mueller from here to here the 180 degrees and splitting up up from here to here the 180 degrees but in half all year around so they're all going to be just 90 degrees Derek number 6 "quotation mark coordination with not happens we take 1 away the only put along parallel well 1st of all In this shape to the matter was tricycle collect and it doesn't right they're all the same basic where you can treat them all the same they all have the same bond angles so and is going to take this wearing them so now we have this sort of shape now are a lectern geometry of course is something to be what skinny oxygen now we have to think about our molecular geometry so this 1 goes back to thinking about what shape looks like so if you look at the base of what I have seen you on display the guys at the square right now you add this 1 and now you have a pure image through its square pyramidal again there's a little bit of memorization there but you keep your model that looks like it's not too bad to memorize it makes sense there's a logic to it undermining the economy less than 90 days because you have all these long hair this long periods pushing everything down or up in this case it's squishing everything a little bit making everything a little bit less than OK so now we get to take away another 1 thing we had to take 1 of these away now the question is does it matter which 1 take so we know that 1 parish of most triples longhairs don't wanna be around each other so we can take it 1 way here and put it right next to long Paris live along pair here along parity here an insane thing with this 1 this 1 of those 1 where do I put directly across from it were now you pair here 1 pair here complete opposites as remarked any idea on individual Monica Rumsey 1 of them on opposite sides to take it from the opposite side we took this 1 from the bottom of this case so sum the top and so we get so now are electron geometry still going to be on the job because we still have electron pair here and electron pair here that didn't change now a molecular geometry so we have a square but it's all on 1 play inside a secure needed something like that so it's square planes now comes the bond angles so before we had said it originally was 90 then would come along pair it was OK now it's less than 90 know what happened put another long apparently place here isn't even less than 90 well if you think about it we have this pushing up with this pushing down in the balls along Paris Alleghany pushing index insulin balance each other out in Syria back to just 90 it's not less than 90 anymore it's exactly 90 this is pushing up with the same amount that this is pushing down and so there's a couple of examples of those on my which really have drawn and this and that being like that for a complete your work she in your workshop send no until they learn keeping all this in mind NGO stopping the sort of build these ads and you need to winning gold after all those Lewis structures that we through Maria aside what on the left front yard trees and the molecular geometries of all program
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so again keeping in mind there are from kinds of a get just because it doesn't really fit so great example that this 1 the Until There's not really a geometry talk about here there's only 2 molecules are there's only 2 items sold were only talking geometries when they're bonded to more than 1 thing so long we're not really going to talk about so now if we look at the sun so seems to ask yourself when you're going through this is what is the start number 1 is the coordination number and then out that water each of your geometries so to assurances of unused ascendancy and for steric number coordination over many years EG & G 4 electron geometry like so if we look at our steric number we have 1 2 3 things bonded to it in no long Paris were just looking at the current rate whereas a mother's long on the oxygen we don't care about the
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accident just looking at the central Adam so 1 2 3 things bonded to it shows for bonds but we can we treat double and triple bond the exact same as we do single bonds so our coordination number and the stock number are both 3 so for the 2nd time discuss extending so if we have them we have 3 things bonded to money is the geometry of space of a mouthtomouth and so were left Woods trickle plainer it's not because electronica because the stairs ,comma coronation brothers saying that's going to be bold it both electronic and molecular geometry the pact so that's that's how we do that once again we don't care that there's a double bond there we just treat that as 1 were not kind bombs were counting numbers of things that are bonded to the atom you can you to this 1 this is interesting fact we to central and so what are we to do while we look at both of them completely separately so we look at the border and then you look at the nature now in this case they happen to be the same blood it's OK so if you look at it's steric number is the same as those coronation because there's no 1 paradigm in both of those are equal to 3 and so we're left with the exact same situation we had in the last 1 these and other incidents something weird going on with the development holders he
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positions like that on right so when the born in nitrogen bringing up in the same thing that we did in the last 1 where we have these 3 and there are evenly spaced and so we had trained on clean after all no we no Westerners for sorry about that streamers Beverly forces natural place now we have for these things space like this where the spacing so if we look at this we have detected he and that's kind of people because our stared member and our coronation Brothers it of having the exact same thing current success him so a nation Finisterre numbers In a coordination number both the coldest 4 of 1 2 3 4 and so were lost to the same thing where we have 4 things bonded to it no longer cares and sorry electron geometry and a molecular geometry of both countries now we have a and C X for Act III at 4 4 4 plus soul singers but for me ,comma stared American ,comma fournation number In this case is the same so 1 2 3 4 certainly the molecular geometry area TransAm trespassing and that's going to be Tatra for the same reason as before we speak small in the most even way possible and that gives us touches it now we have to move on to a N 2 0 and keeping in mind disturbed stable once and again were just looking at a central Adam here a friend Central walkable from the individually so those cases is looking at nitrogen and so the 2 things spaced evenly apart apart cross from each other because this is like a right herds it's 180 degrees across the Suez spread to Adams out in the most even where possible so we're left with a linear geometry so stare number 2 coronation number equals still Henry geometries of the same and the linear isn't that I get a sort of had to sticks with you while you're doing these sorts of homework problems in practice doing them with scenes in your hands that you comply with you can see the geometry of issues have to be really good at in 3
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dimensions located near maybe that's not so important on but a lot of people myself included or not now we have access 6 cells when we look at this 1 and we decide what our coordination number and Torah steric number is we say Well how many things are bonded to a 1 2 3 4 5 6 no pairs they're both the same now we have this Iowa geometry soul if you wanna all equally this is how you not needing do it and so you end up with 6 equally spaced just thing it shaped like an not to see Darren and so active control In the morning dew on the burial get it kind of naming them quickly and may take a while at 1st sort of the other ships in your head now time for a tricky 1 at the F 4 so if we
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have actually asked for a originally will have and steric number of 1 2 3 4 5 6 because the company number of bonded Adams and we come along Paris but not coordination numbers change because the coordination just Council bonded Adams so who have 4 and we tried it Nunavut the shape that looks like this and for our electron geometry so if we have electron geometry that's going to be equal to whatever this looks like which is up to the drop now we have to fit too long parents we have to take 2 of these items replacement lone pairs so again we have to think all Oregon from here and here and a lot of space and questions space so putting along pair hearing along pair here where to invest as a square planar shit every so In costs are bonding goes here show forget From bonding austerity 91 EU well that really started as 90 it's still going to be 90 because long pair here the lone pair here they're pushing on each other equally and so because of our bond angles here are still about 90 OK sir it and so forth remember this is how all of our after that kind of set up so it's good because I keep this structure in line so you remember and we have a oxygen bonded to a central atom and hydrogen offer oxygen so if we look at this and we go through we say Well we don't care these are double bonds we careless offers breaking the architectural known that matters to us for the sake of geometry really talked about why those are all OK so far geometry for the sulfur reality I organize a welder's glass things bonded to it no longer Paris 1 2 3 4 so both its Derek number In this coordination number article the foreign now that means that both its electron geometry and its molecular geometry we penitentiary hero yeah no we only talk to I haven't had to centralize rate is 1 of slain bonded to more than 1 item we can talk about it in the same way so we can do the exact same thing for the oxygen now what sisters who run the oxygen 1 2 3 4 so it's a coordination among the oxygen just 1 to his thinking Roth accidents when there were just talking about the issue not least because these are only bonded to 1 thing OK so now this is still don't be tempted the to 4 things no this 1 we hadn't had reviewed all electron geometry now we have taken 2 of those and we replaced 2 of those along Paris and so that leaves us with a bent geometry but be careful not to treat our has 2 things bonded to must be linear right will know because we still have the electron that we have to worry about so even tho there are only 2 things bonded to it there's these electrons the taking of Rome and so it's keeping in his now where
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Valentine for the date so the goal home in practice doing all of these that we just didn't we had step the bond angle purposes you can go back through them and talk about them again on in the geometry is again a little bit of review in the very beginning next class so will finish a bond angles next class and will finish at the rest of the Lewis structures next time I'm in the meantime go home practice during those you can fill all the bond angles and will check and see if you're right as of next time and then will take what we learned will combine it with last classes lecture we talk about worries have properly area and will actually be able to go through now and say well based on the geometries and the polar bonds which 1 of these molecules are actually polar and which ones are going to people