okay so we're going into the the CPR Theory and the Crystal solids all right the last section of topic two that we need to really cover all right and then that will be the end of it right um and then we probably move into Redux reactions and energetics um and just complete everything with ktic Theory and then into the rates of reactions right looking at log graphs and those type of stuff right so let's get into this all right before we understand how to really construct these vcpr structures and understand molecular geometries for covalently bonded compounds all right we're going to need to remember Lou do structures how we construct Lou do structures how they generally look right so it is a form of chemical representation right so when I speak about chemical represent resentation we know that we can represent chemicals as general formula molecular formula um sceletal formula right there are different ways to construct molecules now the Louis structures right are the best way to show the atoms that participate within bonding in the molecule right and understanding where free and bonded electrons are and how many free or bonded electrons are in the structures that is important let me just see somebody sent something in the chat oh okay just accept that all right so it's really important that we really look at it so we need to understand how these structures really look what we going what's going on with them and then get into examining our V structures the main reason why we really use it is because it tells us what participates how many atoms participate how many electrons participate that's the best way to define our VPR structures all right so let's really look at it so the Louis electron do formulate right so it's a little bit um interesting right it's not really um really difficult but we generally have five steps I would like to look at all right the information on the slides are for you guys to like read when you have the PowerPoint or if you want to skim through it right but I'm just going to go through it right so step one the first thing that we do when we're writing our chemical formulas right we write down the chemical element at the center of the structure now in unit one chemistry we we tend to deal with really simple structures therefore most likely you're going to always have a central atom all right so your central atom is what you draw first so if I am going to draw something like hopefully I don't use on of the examples are in the PowerPoint um I don't remember what what is in the PowerPoint but let's use carbon all right we're drawing methane all right so the first step is just draw that atom of carbon there all right sitting there then the next step is to count the total number of valence electrons for all atoms in the molecule you know or ion all right so we're generally going to be counting all of these things so let's say that we're doing methane we know that we have one carbon we know that we have four hydrogens all right how many electrons would be participating there how many veence electrons do does carbon normally have this is where somebody jumps up and says the because it's so easy carbon has four veence electrons wonderful all right so carbon has four veence electrons therefore we're going to be noting that so the number of electrons from carbon we have four all right so four valence electrons so far how many veence electrons does hydrogen have hen has one one all right and we have four four atoms of hydrogen therefore we're going to have four so we are going to have overall eight electrons now that is important because we need to account for every single electron that is present right for something simple like methane we're going to notice that all the electrons eventually become um well eventually identify with a bond right but for structures like ammonia right it may be a little bit different where you have lone pairs all right so what you're going to do now is connect the atoms in the molecule or ion using single lines and that represents Sigma bonds right to represent these coent bonds and each line would rep represent a pair of electrons all right that's generally so I have four hydrogen atoms so I know that carbon has a Tetra valenty aspect right Tetra meaning four so it has four veent electrons right so what's generally going to happen is that I can note that my carbon has four electrons around it like that and I knowe that I have four atoms of hydrogen meaning that each hydrogen also has an electron and our structure is going to be looking like this right our end product is going to be forming these you know pairs of electrons into bonds right so we're going to initially just we're going to eventually I mean write them like this step four is to place dots around the chemical element for each atom to represent the remaining veence electrons right and make sure that each atom has a complete octet that is kind of well when we start looking at the fact that some elements have an extended octet and some elements are pretty F without filling that well ful fulfilling that you know octet rule then we can look at that especially with you know something like um sulfa hepto hepto fluoride or something like Boron Tri fluoride all right they're going to be a little bit different so you're going to have to know those things that don't follow the oet rule right so we're going to have something like this and we need to account for each and every electron all right now we know that each single Bond counts for two electrons and we have four single Bonds in this compound therefore we have accounted for all the eight electrons right the next thing that we should do is represent everything in pairs of electrons if we have any free electrons outstanding on this molecule we don't have any free electrons outstanding right if the structure is a formal charge add or remove electrons to balance the charges on the atoms all right so formal charge I'm not sure if anybody knows what that is can anybody tell me what formal charge is what is the formal charge of an atom or ion go ahead it's the number of fail and in the new atus number number of non okay so we're going to be looking at that so the formal charge of a molecule tends to well of atoms tend to be equal to as you saying the veence shell you know the amount of electron on the valence shell minus the number of non-bonding valence electrons right and that would be minus the amount of bonding electrons hav right let me just pick to get this in there right so you're going to have something like this it's going to be equal to valence electrons I don't want it to look like electron volts so I'll just use V right for veence electron minus the number of non-bonding electrons so n non-bonding electrons right minus bonding electrons divid by two all right so if that comes up to be somewhere you know above or below zero we try to to rearrange it to make sure that it has at least the least formal charge now some molecules have to have a formal charge because some of them are ions right so some of them are a bit different right um but in those cases the structure with a lowest formal charge which said to which would which will be said to be the most stable structure and the one with the highest formal charge right is the most unstable all right so that's generally what we're working on all right so let let's have a look at something like this all right this is generally the first two steps we look at our Central atom specific specifically so we represent atoms themselves and we place the number of veence electrons around the atoms variously like that so this is our representation of oxygen and nitrogen as examples all right so that is generally how we come up with the structure right I put this extra information here as another tool of explaining how it works all right because there are two general ways right the way that I use here which are just quick five steps but sometimes persons need a little bit more details as it relates to connecting the bonds and making sure there's a full oate and stuff like that so there's more information here as well as how to calculate the formal charge on a molecule all right and this is more in depth because now we are talking about the stability of a molecule generally all right but we're going to get through this should be fine are there any questions though any questions or concerns so if everything is fine so far just drop a one in the chat please just drop a digit a number one in the chat and if there are any questions you know you just unmute and you just let me know even if it's a comment you can just let me know the comment by the way give me a moment let me just verify something on this slide that would be that that over that so that would be all right so the information is right cuz that structure is fine okay so that is it I have to really verify this information because I no longer draw structures with the rules you just when you understand the rules and you internalize the rules you just draw in a structure all right so just comes with a little bit of practice now the L structure for N2 right so this is the information or the tools to draw the L structure for N2 so I want you guys to just go ahead and draw the L structure for into real quickly should take a couple seconds at least at most 30 seconds right just let me know when you're done just drop a war in the chat when you're done with the Louis structure for next for the next molecule please all right so the information there is information is already on the screen it's construct it just let me know when you're done because even though you may already conceptualize and understand how to draw the thing when you draw it a little bit easier to complete other structures um sir um some people want to be that in okay let me just check thank you for letting me know um ooh all right um okay it's a lot of people all right so go ahead are you guys finished with the N2 structure yes no maybe um good afternoon good afternoon we write this down no no no we going to receive the power I thought we were starting six that's why I'm late that's okay I'm not seeing anybody replying about the structure all right so we're just going to continue then all right so the next gas structure tends to form this one all right now before I I continue There are a little bit there are some best practices that I would like you guys to use I know you guys understand that electrons repel each other fine fair enough all right so if you're going to be constructing nitrogen like this please don't leave your electrons like that that's not it right don't leave your electrons in awkward positions all right we try to make sure that they're completely understandable and agreeable right electrons repel each other therefore they will be at the farthest poles away from each other all right so try to represent that's best right the more we draw loose structures and realize that electrons repel each other that's going to be a wonderful assistance in the veence Shell electron repulsion Theory all right so some best practices there we're going to be moving on right so structure of CO2 all right um okay so let's just do the structure of CO2 so we're saying that we're going to have one carbon atom all right in the center one carbon atom and it has valence electrons around it four veence electrons right and then it is flanked by two oxygen atoms right so we have one [Music] two oxygen atoms right oxygen has how many valence electrons six that's a question by the way how many valance electrons does oxygen have six six all right tough cow um I don't know all right so looking at something like this oxygen has six veence electrons therefore we're going to be constructing that around it so 1 2 3 4 5 6 all right so 1 2 3 4 5 six so six valence electrons are on oxygen right so that's what we're going to do first then we're going to try to draw bonds right to make sure that your central atom has fulfilled the octet rule thus far all right and we have to share them so since each oxygen atom would require two electrons to fulfill noble gas configuration and carbon will require four bonds to fulfill noble gas configuration we can just Express that like this right oxygen has its shared electrons now carbon has its four bonds and everything looks fine right so this is General structure that we have for CO2 right a doubly bonded compound all right and if anybody can just generally recall all right what's Happening Here let me not go into that actually let me not describe that actually so let's just continue with this so that's generally L structure for oxygen all right and then here now we have something a bit more complex right the carbonate ion all right so I want you guys to actually try the carbonate ion CO3 2 NE so the3 and we know that the charge on it is to negative I want somebody to try it right right so I won't continue because nobody answered so I want you guys to actually try this one and after we're done trying then we may move on so let me know when you're done with it I'm going to go back to the rules so you guys can look at the rules to have a general understanding of how we draw the structures so try CO3 2 negative it's a really complex well it's a complex one all right so I'm going to just allow you guys to do that when you're done let me know if there any questions you guys can ask as well let's draw the structure let me know let me participate in this structure that's wrong 1 2 3 4 5 6 7 8 that's done 2 3 4 5 6 78 1 2 3 4 my structure is finished it's going to be negative negative all right just let me know when you're finished with your struction all right so Anna is done anybody else completed so see the first person these tasks of completing Louis structures generally take or should generally take us 30 seconds right so when we practice them and go through them then not Max it take you more than 30 seconds then you know we get straight back into the understanding the rules and practicing it shouldn't take more than that if it does then just more practice anybody else completed with structure or we just move on with an alone all right finished sha is finished oh sorry sha is finished Sha Sha yeah all right so seems like majority of you guys are done a good amount of you guys are done because that's not majority but let's have a look at it our carbonates right so let me just look at the structure first that is the structure of carbonate right so it is a polyatomic ion all right so we generally have this structure so the first thing we do we know we put our carbon down we put our oxygen with the veence electrons and then we try to connect using bonds all right so we create bonds using two two veence electrons right of the negatively charged um oxygen right and then we use around well we'll connect that with one Bond right and then we're going to use double double bond for one of the carbon atoms right this will actually give us complete octet right for most of for everything in the compound so far all right and then we're going to have a negative charge on two of the oxygen atoms because they're there are actually you know arranged lone pairs that increase the charge on the oxygen atom right and it's also based off of the formal charge so if you have any issues with the molecule itself right I suggest that you go back to the rules redraw it calculate your formal charges make sure that the formal charge on the entire molecule must be two negative right on this structure here oxygen is fine like this all right oxygen is generally fine with two lone peers and by the way there are anomalies once you practice you're going to be able to remember all the anomalies right so oxygen has is fine with two loone beers perfectly okay all right so what generally happens here now I know oxygen only has one bond in this structure here one Bond let me just use this right one bond in both of these structures right it allows it to have an extra loone pair concentrating extra charge so the formal charge on these oxygen will be1 right we said that the normal charge is veence electrons minus nonbonding electrons minus bonding electrons / two right so if we look at it like that the veence electrons on oxygen right we're going to have generally six veence electrons for oxygen minus the non-bonding electrons 1 2 3 4 5 6 right and we're going to be minusing right the bonding electron which is one over well which is 2 over one actually right well 2 over two sorry about that I'm lapsing right so the sixes cancel we're going to end up with -1 there right so we're going to have 6 - 6 is 0 - one one minus one right so we're going to have a negative charge on these oxygen atoms right and if we're going to have two negative charges we can bracket then Tire on all right and put two negative on it like that all right so two negative that is it everybody's fine with that want in the chat if everything's fine so far and we can move on all right wonderful Okay so understanding this is just what we need to do it's a recap of L start structures and then we head into the vs the Vesper Theory all right so the vasper theory or the V Theory the veence shell electron propulsion theory is a basic theory that we use to predict the structure of coent well the geometry of coent compounds right could say the structure as well it's all based off of molecular interactions or electronic interactions with at species or we could just say lone pair bond lone pair interactions Bond pair interactions right so we generally look at the repulsion of electrons and in this case we normally look at the fact that electrons are negatively charged so they're going to try to find the best way to always you know be a furthest apart from each other right as well as bonded species right if we have multiple atoms around an um a central atom they're going to actually spread apart right to make sure that they're at the maximum distance apart right so that's the main understanding of the VPR theor and what we need to really get through all right so we have some postulates here some really important postulates right so the first one I'm going to be going through all them verba off of the slide by the way so the first one all the electron pairs in the molecule are arranged in such a way that they minimize the repulsion between the electron pairs of the atom right so they spread out furthest distance apart that's basically what the first one is talking about the second one is that the central atom of a polyatomic atom right um of the AP polyatomic atom right is the well would should be a molecule right is the atom to which all the other atoms of the molecule are linked right so it's generally something like that so some things can be binary something can some um molecules can contain the same atom specifically right and some um can contain different atoms right cuz some elements tend to be able to Bonded bond to each other right the same element for example carbon carbon chains right so in a species where you have a different Central Atom from all other bonded atoms right we're really looking at this all right um it's a little bit detailed but yeah Valenti electrons of the molecule are responsible for the shape of the molecule right that's what we're looking at the veence Shell of the molecules is arranged in such a way a distance is maximum right and therefore repulsion is minimum right so a lot of these things kind of drive home the points a sense in a sense right if the central atom of the molecule surrounded by bonding pairs right then the asymmetrically shaped molecule is formed right so we're going to have an asymmetrically shaped molecule we're going to look at how that works right why is it asymmetric right then if the central atom of the molecule surrounded by loone Pairs and bonded pair electrons then the shape of the molecule um that is formed is distorted and we're going to look at molecular Distortion or geometric Distortion right then in each resonance state of the molecule where we going to be ex experiencing resonance States and stuff like that a little bit um sooner than expected all right but it's really used for unit to right and then the force of repulsion between the loone paers right so loan peer loan paer and bonded peer and bonded paer follows that order all right now this is a lot of information right it's there to read but I'm just going to guide you through it now all right this is the order in which the repulsion follows all right if you have a lone paer of electrons repelling a lone pair of electrons that is the strongest interaction all right if we have a lone pair of electrons repelling a bonded pair of electrons using the line to represent a bonded pair of electrons right then that is weaker than Lo pair loan pair interaction and then the weakest interaction is Bond pair interaction with Bond pair interactions right so you can see some of the examples here and we're going to explain in each structure why we tend to get these geometries all right so before I move on and completely explain what this has to do with molecular shape is everybody following the far yes any questions so far the diagram there all right I'm not hearing any questions hello just a reminder that you can always ask a question at any time and you can always stop me in the middle of speaking and ask a question all right but yeah so let me completely explain this now all right we're going to be using it to predict the shape of molecules all right but the I'm going to get into the shape of molecules so I can explain how oh someone was speaking I apologize can you go ahead please my apologies can you hear me now yeah I can hear you now oh my gosh cuz I was speaking earlier and I was like are you ignoring me or something no um the diagram there doesn't really make sense I don't understand it okay the diagram doesn't make sense all right so let's use the diagram so okay let me just ask one more question what about the diagram doesn't make sense it looks [Music] fine the second part with the brackets around it okay so the second one back around all right so what we're seeing let's look at water all right this is wrong by the way um definitely so I'm just looking at diagram properly and realizing that that's not good all right so let me see if I can give me one moment please I can hear that at the exact same time I'm hearing them so if I turn this off I can't hear them no turn yeah I can't hear them when I turn the one down that's I'm explaining that to you right now yeah so not hear anything hello you still in the game but if you turn on the master volume that turn on everything coming all right on you turn down everything so you don't need to turn down everything okay all right sorry about that all right so let's continue like this so let's look at a water molecule all right so the water molecule generally if we have the Louis structure let me do it on a completely different page so I make sure that this makes sense I'm going to be a little bit late for you to all right uh all right so let's draw water all right oxygen is a central atom oxygen has 1 2 3 4 5 six veence electrons then we're going to have hydrogen let me draw it like this hydrogen here hydrogen is going to want a bond right with one of these electrons so let's say that bonds with this electron here forms a bond like that all right so what we're going to end up with is Bond like this or we're going to end up with veence shells like this well veence electrons like this make sense so far no can do that again please okay all right so let's start out right so when we draw our Central atom right so first thing we do is draw the central atom right oxygen and we display it with its veence electrons oxygen is in group 16 therefore it has six valence electrons right so just going to draw some valence electrons around the oxygen following yeah all right so in water water is H2O right so oxygen dihydride right so we're going to have this like that we have two hydrogen atoms right so let's just display the two hydrogen atoms somewhere around the oxygen and each hydrogen atom has one electron to share in calent bonding all right now what the first thing we're going to do we're going to use single bonds all right we're going to be using single bonds to connect the atoms together and then after that then any type of um opening for double bonds or triple bonds then we add them in but so far we're going to try to connect everything in the compound or the molecule well this the compound anything in the compound with the single Bond right so we know that all of them need to be bonded together so we're going to start with using single bonds so I'm just drawing this around these electrons to say I'm choosing that electron on oxygen to just you know bond with right so we're going to make bonds out of these and when you electrons are shared we're going to have single Bond like that we're going to have these electrons left over make sense because one 2 3 4 is not bonded yeah it makes sense but I thought they were supposed to be like at the F the maximum distance possible so I expect like the O in the center and the AG them like West East okay hold on this what you're expecting all right so I understand all right but give us one moment now to understand how we even get this weird structure of water right um geometry of water right we have we have to use the vpr3 now the venal electrons here and here has high repulsions with the bonds all right but yet again we have to actually look at the molecule itself in a 3D structure all right so what's going to happen here is that the electron the the bond pair electron pair or lone pair interaction is going to be extremely strong so what generally happens in water or molecules that have this General structure they're the electrons are going to migrate to form something similar looking to this all right let let me not bend that yet right so one electron sphere of influence is going to be there one electron sphere of influence is going to be there they're going to be repelling each other so they're at that specific angle right now we can't have this in a linear Arrangement because we're going to have electrons repelling the electrons in these bonds we're going to have lone pair bond pair repulsion right and that's going to bend the water molecule into the structure that we normally see it in all right I'm going to clear up here right and clear this so we can see what's happening all right so the electron pairs are here one two electron pairs lone pairs right and when it bends it it's going to move these bonds to migrates at a specific angle right so we're going to end up with the lone peirs at this angle here and the bonded paers at this angle all right so the bonded pair and the lone peers repel each other and since lone paer interaction is stronger than bonded paer interaction the bonded the bonded pairs would be you know brought closer to each other more so than the lone pairs right because we did state that lone pair lone paer interaction is the strongest of all interactions right then we tend to have loone paer Bond pair interaction then Bond pair bond pair interaction so this interaction here this repulsion here is the strongest interaction right then these interactions off the side here the second strongest interactions right and then we're going to have this interaction here the weakest interaction all right so because of that Dynamic right the electron the lone peer interactions being much more stronger L peer P more um more strongly than bonded peers it's going to be pushing the bonded peers into that angle or it's going to be pushing them down are you understanding what I'm saying the persons who had issues yes sir all right so it makes sense so far so far so it's only pushing them all right it pushes them in an angle fortunately for us us as chemists right we have to know all these angles for water water is a bit different cuz water tends to be water I don't know water is just different all right in every single case possible water is different right not only can it exist in all states at one temperature but it tends to form a less dense solid and it tends to have a different Bond angle all right can anybody just remind me of the B angle of water what is the B angle Bond angle of water you guys in biology already you know unit one.5 wonderful 104.5 de right so that is the bond angle of water but for General bent compounds right we call this a bent geometry it's bent or we call it vshape so it has that bent geometry because it looks as if you know you held the hydrogen bonds and just bend it right so it has that type of geometry right molecules that tend to have a bent geometry tend to have a specific Bond angular we're going to be looking at that and the fact that H hydrogen bonding with oxygen in water tend to create this smaller Bond angle than usual right um we should be ending in the next hour all right so we're going to have this structure here now what this diagram is entailing is that if we were supposed to submerge water in an acid which we already know we're going to create an hydronium ion right really really simple stuff we're going to create a hydronium ion what tends to happen is that water itself just explaining this because somebody asked the question right so we're going to have water itself having this structure all right so we're going to be having no we're going to be having this General structure right in which we're going to have one lone paer remaining on the molecule and this lone paer is still going to exert a force on all other bonded pairs pushing them down right so we're going to have a distortion so it's not that okay one loone paer is gone because it's bonded no it's going to be flat no it's not going to be cuz we're going to still have that lone peer repulsion right making sure that this geometry now becomes trigonal planer well not trigonal planer trigonal pyramidal right with Bond angles of generally 107 right point something but we're going to be looking at this all right we're going to be having a look at this so I just wanted to explain like what these are right the explain what these are how it looks right water is a different Bond angle for each of its structures right generally we're not going to really explain why it has that all right but we're going to have to know that it does all right and then we have am ammonia down here that tends to have the correct Bond angle so 107.9 for that structure and then 109.5 for tetrahedral structures all right and we're going to get into it though right but there are there any questions here though no no sir all right give me a second can anybody here visualize it properly I want to make sure you guys can visualize it just let me know if you have an issue with visualizing it and I'll see if I can attend to that issue all right I'm not hearing anybody saying that they have an issue visualizing these all right so let's just move on so we are going to be predicting these ships now a v number right so we tend to have this right so the vcp number of a molecule is the number that describes the shape of the molecule all right so when we talk about the number we're generally talking about the sum of Lone Pairs and bonded pairs in a molecule right this is a really really really simple way of looking at it right really really simple way of looking at the geometry but I want to make sure that you guys completely understand the geometry so we're going to be looking at a more advanced Table after we go through each of the structures individually all right so let's start with the first one the most Sim simple one right linear shapes shaped molecules right now A molecule has a linear shape meaning line linear right a very straight shape right if it tends to have two bonded species right so two bonds right but no lone peers so two bonds right and no lone peers no LPS so it tends to have that straight geometry and an example is burum um D fluoride right so burum D floride is a wonderful example there so it tend to be linear we're going to be looking at them I want to show you guys a simulation of these molecules right we have a trigonal planar molecule right when we have three Bond peirs so we have three bonded pairs three bonded peirs all right and no lone peirs three bonded pairs no lone pairs so we have this type of structure right for example this structure is can be exhibited by or Boron Tri fluoride that we looked at before so Boron Tri fluoride tend to have this structure with the fluide surrounding all right it's going to have this structure not sure why that is acting up but yeah so that is General structure of a trigonal planar molecules right if we have tetrahedral molecules right this tends to happen when we have four bonded peers and no loan peers right the information is on the slide by the way just going through it so all of the electrons participate in bonding and we have four bonded pairs around it right so four species surrounding a central atom have the tetral shape such as um in the methane molecule all right so we have that like that we tend to have a structure that is trigonal by pyramidal when we have five molecules attached to a central carbon for example in phosphorus pent fluoride all right so that is another one there and we tend to have an octahedral shape when we have six different atoms surrounding the central atom as in Sulfur hexa fluoride right and so sulfur in this case would have an expanded octet because it can accommodate more electrons than eight electrons right cuz in this case it's it's accommodating right 8 9 11 12 electrons right around its Center on its veence shell so this is just a little bit of an introduction into the fact that the maximum number of electrons on a shell is not eight it goes past the number 20 I think it even goes past the number 30 right so things do happen all right so this is an example of an of a molecule containing an expanded octed all right so if there are any questions about that or in examples must be given this is a wonderful example all right are there any questions so [Music] far all right so this is a general um table that we look at for that I look at for geometries all right so it's good to memorize a table if you would like to right e shows the central atom X shows peripheral atoms right so atoms that are bonded to the central atom and here we can know the different um geometries generally right so if there are two electrons but no lone pairs that would be linear all right if we have two electrons and if we have three electrons and no lone pair that is trigonal plan R but if we have three electrons but we tend to have a lone pair right then we're going to have a different structure we're going to have trigonal pyramidal right so we generally have to look at stuff like this right we have to really look at it to understand the different structures so this table is really good and I do recommend that you guys understand the table look at it a little bit and play around with different structures right also the wedge um system the wedge hash system of molecular um representation is important for us to understand before we go on crystalline solids right um I'm going to need hopefully a little bit more time okay if I don't complete the PO point in time all right then crystalline solid is really small and all the information for crystaline solid isance on the slide so I'll just send it to you guys and if you have any questions you just ask me the group all right just in case I don't finish that all right but the wedge and hash model right of electronic representation right we generally have something like this what structure would this be this would be the Louis structure of water right General Louis structure um I think water is a bad example um let's use probably ammonia let's use ammonia as example all right so we have ammonia here Louis structure of ammonia would look like this right generally it would look like this and then we'd have a loone paer like this right based on villain selection pair repulsion Theory where we have four bonded species well we don't have four bonded speci we have four electron species right four things surrounding the nitrogen we have 1 2 3 four things surrounding the nitrogen right three of them are bonded and one of them are not right based on the T table here right we have four things surrounding three of them are bonding and one of them are not so we're going to gain trigonal pyramidal geometry right so we end up with nitrogen right it's generally just looks like a pyramid right so that's it right so we're going have a nitrogen and we're going to have one hyrogen within the plane right so within if you're writing this down on a paper or anything like that that's going to be within the plane of the molecule all right then we're going to have one of them coming out towards us that is what we use the wedge for right and then we're going to have one of them going behind into the plane of the page which is the one behind and then we have that loan perir there so the the blocked in edges right would represent anything coming towards you the hashes mean anything going away from you all right so that's how we represent the threedimensional molecules on a two-dimensional plane all right but before I think I'm going to end generally here all right but I want to look at the molecules in a threedimensional way before we move on on before we just end so give me one moment for me to launch the program so we can have a look at some of the geometries that we've been speaking about all right are there any questions though before we move on before we just look at the geometries and then call it an evening no all right so just give it a second