to First explain bonding and geometry in our complex ion exploration challenge the transition models apply veence Bond Theory so we may remember carbon man um from chapter 20 organic molecules we've learned a bit about veence Bond theory in hybrid orbitals of carbon when it makes certain bonds so for example we have carbon man here and as you can see he has the ability to make four Bond now these are going to be considered single calent bonds that come from sp3 hybrid orbital so we know these aren't just lines these are going to be specific hybrid orbitals that are created from mixing Atomic orbitals of carbon to create brand new hybrid orbitals that allow us to understand how carbon can make stable Bond okay so we see here that our carbon is going to be bonded to hydrogen we have a carbon here bonded to hydrogen and what we really are saying is that the sp3 hybrid orbital is overlapping with the or oral for hydrogen and so that overlap is allowed them to create that end to end overlap and that sharing of that electron is allowing them to create a sigma Bond or a single Bond here and that Sigma Bond creates 109.5 degree Bond angles okay between each of our electron groups here and because of that 109.5 degree Bond angle we actually have a tetrahedral shape okay so let's go ahead and think about that if you know that you are kind of like already getting confused by those little details or this manyi review you can always go back to brush up on some of those details from kim11 but the goal here is understanding that veilance Bond theory is going to be mixing Atomic orbitals to create new hybrid orbitals and those hybrid orbitals are the orbitals that are used in creating Cove valent Bond okay so we want to apply this kind of theory to help us understand complex ion and Beyond just applying it to create the new hybrid orbitals like I just talked about we also want to add in the other layer which is the shape so because these sp3 hybrid orbitals are formed and they're going to be forming Sigma bonds of course they can form Pi bonds as well if you're going to be having double and triple bonds and we're thinking of veence bond theory for like our main group elements like a carbon right when we're thinking of that yes you can have your uh your single triple and double bonds so your sp3 hybrid orbitals SP2 hybrid orbitals and SP hybrid orbitals that we talked about in chapter 20 yes folks that is true we know that we know when those overlaps happen shape is going to be in form so when we're talking about complex ions we want to kind of think of the same thing complex ions we know that we're going to have our hybrid orbitals and our hybrid orbitals are going to help us understand shape and so just keep that in mind as we're going through all right folks but how do we simplify the bance bond theory for our set we said that we had a carbon and depending on the amount of things surrounding the carbon that's going to allow us to know the number of atomic orbitals to mix and of course that's going to allow us to understand the number of hybrid orbitals that are formed so for example if there's four things surrounding the carbon that means that we're going to need four Atomic orbitals and the atomic orbitals are going to be the S and P orbitals so there's one s orbital and there's three p orbitals right and so those four or are going to mix to form four sp3 orbital so we want to make sure that we're basically applying all these little details to complex ions like I said before so we will see that complex ions will have their own hybrid orbitals that help inform form shape so remember the goal is that we're trying to understand why we have the different geometry we have and so just by applying veent Bond theory is going to help us understand the coordinate bonds from a complex ion and the shapes that in form all right folks let's get into some of the detail okay first when we know when we're talking about complex ions that means we have a metal ion okay that is bound to a Li and if we explain this using veence Bond Theory we can say that we have a filled orbital of the Lian so a filled orbital of the Lian is going to overlap with an empty orbital of the metal ion so the question becomes how does this overlap happened when we saw the overlap here we got Sigma Bond so how did this overlap happen here we know secondly if we're talking about complex ions we're talking about a leis acid base reaction that means that we're going to have our metal ion okay that has the ability to act as a l acid meaning it's going to accept electrons and where it's going to accept electrons from the leis base so we have our metal ion is going to accept electrons from our Lian or the L base and once it accept those electrons we have a l acidbase reaction that occurs and of course we're going to form a coordinate calent bond in a Lis acidbase charge complex ion we saw that before we have our for Bond and we know that this complex ion can have a charge you can also if we want to apply this with ve Bond theory of course with complex ion then we want to say that we have an overlap in from end to end so again we're trying to add in different language now we're saying we have an overlapping of end to end of the metal ion acting as a leis acid and the Lian acting as a leis base so they're going to overlap into in that means they're forming like a sigma Bond if you will and of course um the coordinate calent bond that is formed is based on that end to end overlapping all right folks and of course this overlapping is going to create this metal Lian leis acid base complex and that is what we see here so all we're really doing here is taking some of the verbiage and adding different layers to apply it to our complex ion okay so what else next we can basically uh the finally take our bance bond Theory concept of mixing Atomic orbitals to create new sets of hybrid orbitals and apply it to complex ions so first let's think about what veence Bond Theory says about our atomic orbital mixing let's think of ch 4 that means we have a carbon with four things surrounding right and so that means we're going to have sp3 hybrid orbitals we have CH4 and we have a carbon with four things surrounding it okay and so we know we're going to have sp3 hybridation we also can say the same thing if we had a carbon like say our carbon was double bond to oxygen with the carbonel group and we had a hydrogen we can say that we have three things surrounding this carbon and so it's going to be SP2 hybridon and again how do we get this we basically mixed Atomic orbitals from the carbon the central atom here our carbon we took Atomic orbitals from the veence shells and we were able to mix them so we took an S orbital and we took three p orbitals and we mixed them to form sp3 of course there's four of them here we took an S orbital and two P orbitals and mixed them to form SP2 and there's three of them and they're all going to be in equal energy so that's what we want to apply to veence bond Theory we want to basically make sure we're saying how many ligans are now surrounding our Central metal ion and because of that what type of hybridization or hybrid orbitals are going to be created and because of that what kind of bond angles will it have and because of that right what kind of shape will we see so let's go ahead and add those layers next now I do want to make sure that you are realizing this is a flash card so I would definitely have on my flash card um probably number one here and number two and then for this third one I would use the next um portion to basically add in a little chart so in the front I would put like veence Bond theory for complex ions on the back I would say it has to have a metal ion Lian it has to have a leis acidbase reaction and all the products from it and it also has to be able to mix Atomic orbitals which we will see next so again on the back I would have linear tetrahedral Square planer and then octahedral is really the Big Kahuna for us it's the one that we're going to focus on a lot when it comes to um pretty much the rest of the lecture you're going to see when it comes to Crystal field Theory our only focus will be octahedral bance Bond Theory I'm going to show you all the different hybrid orbitals but again you might see a lot of octahedral as well so just keep that in mind so we're trying to apply veence Bond Theory to our complex ions the goal is that we have a central metal so here's our Central metal in all these different um hybrid orbital shapes here and the central metal depending on how many lians are surrounding it is going to help us figure out how many um orbitals from the atom which is going to be the orbitals from the central metal ion how many orbitals from it are going to mix to form new hybrid orbitals okay so that's what we're thinking of here and why is this important because the geometry of the complex ion is going to depend on the hybridization of the metal ion so first let's always go back and say what is hybridization well again we know there's a number of things surrounding the central atom but for complex ions that is now going to be the number of lians so if we go back to the previous part and think about that and we say wait a minute didn't we count the number of lians surrounding a central metal ion and we called it the coordination number guess what we did so when you know the coordination number of the complex ion you can also go further now and get his hybridization SL type of orbital used to create that coordinate coent Bond overlapping so this is all going to be based on the number of ligan surrounding that metal ion which in turn explains the geometry folks yes it connects so we do have our four hybrid orbital shapes that can Pally form um we have our linear our tetrahedral Square planer and octahedral like I said before so for the linear shape we still have two lians surrounding the metal ion and so when we have two liens Sur surrounding the metal ion we still are going to have 180 degrees and so you can look at the metal here in the center and then the Lian here as well and these are going to be taking an S orbital and a p orbital so I just want to remember that we always understand there's always One S orbital is three p orbital and 5 D orbitals so because we're dealing with transition modals a lot yes you will see D orbitals come into play here so for tetrahedral we have four ligans surrounding this Central um metal ion and so that means we're going to have the metal here we have a Lian a Lian we going to have a Lian coming out this way and a Lian coming out this way this is going to be sp3 hybridized and the shape here is going to be tetrahedral so I just also want to make sure I put linear here and up there I just got to rewrite it mess up okay get another color and the bond angles are going to be 109.5° so that's going to allow us to be able to have this tetrahedral shape that we see here now for sp3 what is that really saying that's saying that the bonds that are in between here the bonds here the bond here and the bond here bonds here and the bonds here so far are overlapping so the sp3 hybrid orbitals from this Central metal ion zinc here is overlapping with the orbitals of the ligans here and that overlapping is causing those potential Sigma bonds because remember we're talking about coordinate calent Bond and so because there's only one pair of electrons being donated then that's what we can basically get away with poly Sig okay let's move on to square planer now we know that square planer also is going to have four different ligans surrounding the central metal ion so it is going to be using four different Atomic orbitals but because the metal ion is in a different orientation here and it's going to be flat for example um and it's only going to be in a flat Square plane as we see it here the angles are actually 90° and so we do not end up using every single orbital um like we have before we don't use all the P orbitals we actually use a d orbital SP P2 and some folks might say wait a minute why are we not using the other p orbital well it's all about the most effective overlap remember we're trying to create these orbitals here for this Central metal ion and we're saying that they are dsp2 orbitals and the goal is that these orbitals are overlapping to form the coordinate coent Bond and so you want the most able effective overlap and unfortunately in the shape that we have here in this Square planer shape because of the shape the best overlap would be with an actual D orbital then it would be by adding the other p orbital in here and so the orbital here would actually be dsp2 little bit different than what we're used to seeing right now because we're talking about tetrahedron and squ planer and we know that there's four things surrounding it remember that when it comes to different type of exam questions Etc this will be specified for you okay so in the question itself it will say here's a compound that is square planer what is the hybridization that means you don't have to figure it out you would just have to know hey hybrid orbitals for square planer will be dsp2 now let's go ahead and talk about octahedral which is what our main focus for the course is going to be things that are octahedral we have our Central metal ion and then of course we're going to have are different liens surrounding it and the different liens are going to be six of them okay now we can say okay it's a coordination number of six so when you have these six different liance surrounding you that means you're going to have and need six different hybrid orbitals so what we end up doing is basically using 2D orbitals sp3 okay so use all 2D orbitals sp3 not all 2D orbitals all P orbitals and then two D orbitals that's what I'm s saying so this means that in order for this to have the best overlap so in order for these d2s P3 orbitals to have the best overlap here with any Lian surrounding them they need to use an S orbital 3 p orbitals and two D orbitals to accomplish that and so that's what we see here folks so again you can want to start making sure that you are putting all the details down we have SP linear sp3 tetrahedral dsp2 which is going to be square planer and D2 sp3 which is going to be octahedral now for octahedral you're are going to have 90° angles as well that are created and so this is how our veence bond Theory the overlapping of these different hybrid orbitals connect to geometry and how they all brought together one thing I will say is that magmillon will often write sometimes this de orbital here so for example um you will see it written like this in magmillon Sp 2D okay or sp3d2 2 for example but for our exams you're going to write it as we see here so you're going to actually just simply write it as DSP 2 you're going to put the D orbital first so dsp2 here and the D2 sp3 there if nothing wrong with wri in the other way like like you'll see in McMillan there's nothing wrong with that but it's really a preference in notation but I'm just saying as far as like practice goes my brain is going to automatically put dsb2 and so the examples you see in the exams will also put the D orbital first so that's why I just want to make that clear for you okay folks also again flashcard moment you can put complex ion hybridization on the front um you can also put veence Bond Theory the front and on the back you can put all three hybrid orbitals the geometries the Angles and make sure that you add in the fact that we have to have that metal Lian Bond the fact that we have to have a LS acidbase kind of reaction with the overlapping of these hybrid orbitals and the liens themselves so a lot of little details now of course the last thing we need to do is get into some examples Okay so so first you want to read the question and then you want to pull out any words that can help you connect the material so this says what type of hybridization according to veilance bond Theory does a square planer Platinum exhibit in the complex ion PT NH h34 2+ so first we're talking about hybridization that means I have to make sure am I talking about linear am I talking about tetrahedral am I talking about um Square planer am I talking about octahedra that's what we need to know I'm just going to start writing that down and of course this is based on bance bond Theory we also know from bance Bond Theory you have to have metal lians uh complex that is formed from that coordinate poent Bond now we're talking about Square planer here just from the question so if it's Square planer I know I need to be focused on the fact that'll have this type of hybridization now they give me this complex so I'm going to go ahead and write my complex here okay and what we need to know is we can always say well what is the coordination number of this complex as well because that's going to help us with hybridization so I will look at my central metal ion here and I will look at the number of liens that are attached to it this is a mono dentate Lian so that means you can also go back to your Lian chart that's actually given to you on a practice exam for example and just verify that these lightings are not by Dent so you don't have to make any multiplication here this is all model Dente so this only has four things surrounding it they're saying that it's Square planer so I know that these four things are going to be the Lian here here here and here and so I would say that the answer here would be dsp2 I need four things at Square planer four things surrounding the central metal ion so that means I have hybrid orbitals of dsp2 next it says what type of hybridization does the Cobalt exhibit in this complex ion so again we have our complex ion we want to verify that each of these whether or not they monodentate or B dentate both bromine and and our water are going to be monodentate so that means we have four Waters and two bromines attaching to our our Cobalt so the coordination number here is going to be six and so that means we're dealing with something that is octahedral okay so that means we need six different um orbitals or hybrid orbitals to make those six different metal liting bonds folks so let's just say I have a metal you have a Lian here a Lian here another lion here here another Lon here and another Lan here so we need six and that is going to give us our D2 sp3 here and so that's three four five six different orbitals or our six metal liting Bond so I would this is how I would approach this type of question and I just want to let you know that the bance bond theory model is easy to help us picture and rationalize bonding and shapes but it's not going to give us any insight into any of the properties that we're talking about we have to go further and use other models like Crystal field Theory and as we go further in the lecture you'll even see that these models are too Cruise sometimes you have to go even higher as you go and learn more about chemistry in the future in our ganic needs all right folks see you in the next video