Lecture 08. Chemical Bonds

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Lecture 08. Chemical Bonds
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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: 0:01:57 Types of Bonds 0:04:30 Energy of Ionic Bond Formation 0:10:46 Lewis Dot Symbol 0:11:58 Ionic Bonds 0:14:50 Covalent Bonding: Molecular Compounds 0:16:04 General Lewis Structure Guidelines 0:19:11 Non-Octet Breaking Examples 0:32:48 Formal Charges 0:48:37 Breaking the Octet Rule
Semiotics Setzen <Verfahrenstechnik> Flammability limit Nonmetal Metallbindung Methionine Chloride Chlorine Metal Molecule Shear strength Electron Library (computing) Covalent bond Vimentin Mashing Walking Aluminium fluoride Katalase River source Erdrutsch Electronic cigarette Elektronenaffinität Cobaltoxide Complication (medicine) Ice sheet Wursthülle Lewisite Endotherme Reaktion Ionisationsenergie Atom Process (computing) Area Setzen <Verfahrenstechnik> Nonmetal Sodium chloride Ionenbindung Chemical engineering Carbon monoxide Carbon (fiber) Man page Chemistry Induktor Process (computing) Ingredient Sodium Valenzelektron Valence (chemistry) Covalent bond Chemical structure Electron Soap Revenue
Semiotics Chemical element Reaction mechanism Sodium chloride Valence (chemistry) Chloride Wursthülle Lewisite Metal Wine tasting descriptors Little Ice Age Electron Ionisationsenergie Common land Gemstone Chemical structure Elektronenaffinität Chemical element Metal Semiotics Ionenbindung Octane rating Formaldehyde Minimale Hemmkonzentration Iodine Chemical reaction Chemistry Erdrutsch Electronic cigarette Sodium Valenzelektron Valence (chemistry) Chemical compound Elektronenaffinität Electron Butcher Thermoforming
Chemical element Aluminium Growth medium Atomic number Chlorine Ice Potassium Electron Chemical structure Library (computing) Chemical compound Covalent bond Periodate Chemical element Walking River source Stockfish Wine tasting descriptors Electronic cigarette Lone pair Molecule Chemical compound Cobaltoxide Common land Thermoforming Stuffing Stereoselectivity Valence (chemistry) Lightning Lewisite Formaldehyde Fluoride Magnesium Combine harvester Lactitol Common land Sea level Butcher Natural competence Atom Area Semiotics Stickstoffatom Ionenbindung Reaktionsgleichung Chemical engineering BET theory Singulettzustand Honey Carbon (fiber) Electronegativity Hydrogen Valenzelektron Valence (chemistry) Covalent bond Chemical structure Electron
Setzen <Verfahrenstechnik> Trauma (medicine) Stickstoffatom Chemical engineering Economic sector Carbon (fiber) Hybridisierung <Chemie> Atomic number Electronic cigarette Hydrogen Electron Functional group Molecular geometry Hyperpolarisierung Singer Corporation Covalent bond Boron Chemical structure Oxide
Chemical element Stickstoffatom Octane rating Fluorine Aluminium fluoride Adamantane Electronic cigarette Hydrogen Electron Noble gas Functional group Faserplatte Chemical structure Cobaltoxide Thermoforming Hope, Arkansas
Sense District Valence (chemistry) Bacterial adhesin Wursthülle Lewisite Formaldehyde Molecule Island Electron Noble gas Honduras Chemical structure Faserplatte Ausgangsgestein Periodate Waterfall Chemical element Potenz <Homöopathie> Stickstoffatom Chemical engineering Walking Formaldehyde Florence Carbon (fiber) Erdrutsch Californium Electronic cigarette Carboniumion Lone pair Hydrogen Valenzelektron Functional group Valence (chemistry) Chemical structure Electron Cobaltoxide Atom
Chemical element Insulin Phosphorus Aluminium Operon Electron XENON Dark Matter Search Experiment Chemical structure Helium Periodate Chemical element Survival skills Sulfur Aluminium fluoride River source Atomic orbital Attitude (psychology) Schwefelhexafluorid Cobaltoxide Beryllium Thermoforming Valence (chemistry) Wursthülle Lewisite Formaldehyde Lithium Setzen <Verfahrenstechnik> Area Set (abstract data type) Stickstoffatom Periodic acid Chemical engineering Fluorine Formaldehyde Asset Carbon (fiber) Hybridisierung <Chemie> Californium Carboniumion Hydrogen Valenzelektron Initiation (chemistry) Molecular geometry Valence (chemistry) Iron Chemical structure Boron Electron Atom
Reaktionsgleichung Chemical engineering Sulfur Wursthülle Atomic number Electronic cigarette Systemic therapy Hydrogen Song of Songs Electron Carbonic acid Schweflige Säure Chemical structure Cobaltoxide Process (computing)
the city will start attempted to enter Chapter 2 is going to start off with a lot of revealed almost any delay thought you needed to know a lot of this before we really even got started with class I talked about it earlier but we should go over it
again in this nature it's cemented in there before we start talking about more complicated aspects of Chapter 2 soap where can go through Morgan remind you of engine covalent bonding so you remember exactly what that is and what the differences are because it becomes really important here all year is still really important here and knowing how to identify between each 1 is very important now working introduce .period symbols and a little bit more formal nature before we can answer about said This isn't really simple ones is how we represent them now administering do a bunch of very complicated ones that they go away more into depth on what exactly is going on which will lead us into trying to talk about how molecules look like and doing geometries and things like that there is moralist ostriches area more complicated and more moralist ostriches really ensue is kind of all about was structures and getting got at that once we really got that down tax we're going to go through induced bond strength in length on comparisons so that we can see how they're related to each other so you know again some relief from last time sold bundle is all about trying to figure out how to complete on cats or make things more stable than the work now you can do that by in something like this case sharing electrons and 2 different electrons have 6 valence electrons Bacongo go share that they can take 2 of the electron share with each other and some bombs there so that they each have 8 there's our 3 main types of bonding we have our atomic bonding are covalent bonding and a metallic bonding revenues are important for knowing happening because we use different names for intermediate ukulele during different from each other so enamored to trading electron sodium says Hey I have an extra electron in chlorine says Well I don't have enough and so the sodium and gives its electrons to chlorine sodium comes the 1 plus chloride in becomes the 1 mine they share the electrons the switch the electrons now that plus and minus another attracted to each other the little man straight so there in the attracted to each other and that's how for now something that's called women on the other hand there is a shared the electrons to something like carbon monoxide carbon and oxygen both don't have quite enough electrons so if they share some of them now they can each have what they need and so they're kind of stuck together by the fact that they're sharing the electrons now we know how to differentiate between the 2 right so the winner you decide whether was something that Honecker whether something's covalent is for right now see where they are in the periodic table so if something's on the right side on the left-hand side not to even things like sodium and chloride you have a metal and non-metal that means that you're going to have an something that's covalent will lead to non medals so everything up in the top right hand corner of the periodic table if it's made up of things over there that's going to be covalent now this is a little bit of oversimplification in toward the end of the chapter we will start talking about how this isn't quite exactly how things are and they're really there's ingredients something the moronic than others and you can have a purely clearly kept II purely covalent compound and then there's sort of agree all the way up until the ionic ones and so we'll talk about that later and then we had the metallic which we are talking a lot about now and you'll get a lot more income would be where we don't want help for a little bit in the main difference here is that all the electronic do localized in that 1 article election doesn't really belong to any particular Adam and so this this kind of sheet of Adams and she electrons are bonded together which means that you can pass electrons through it if you put electron in 1 side you can make it come out the other and so that's why the conductor now this is sort of knew we didn't quite get into this before and there's although other background here that you sort need to make sure you know from the fundamentals that maybe you glazed over a that so all the processors that consume energy are called and no sustained back to your high school or 1 of its key experiences and and think about all of these words coming back to you again right for taking an energy that and for bringing in energy if you're releasing energy years but eateries soaring energy out that axle family right think XO skeleton on the outside putting energy out into the environment world going really far into their income when the 0 we just need to be able to remember what an affair make what exercise like the signs are related to us so we want to talk about the energy of a dynamic bond so think about before I assure you the next slide which has a lot what I said before about how we formatted In electronic goes away from 1 it goes to the other Adam and then the plus and minus are attracted to each other so we have 3 kinds steps that we have an ionization energy and I II and III below the electron pulled off an atom we have an electron affinity In electron coming into an atom the other 1 and then we have this the energy that comes from the attraction of a plus and a minus in we had that energy source 3 energies and for it to be favored we wanted to be accessed and we wanted to
give off energy if we have to put a bunch of energy in the form something that's not the favorable since the sort of the background for the next slide OK so this is what I just said all kind of Lido formerly 1st this 1 we have sodium using electron we have an electron going away from the Soviet now we have a word for that right we talked about it just last week on lecture we called that ionization energy and electron is leaving so the only real difference here instead of talking about a trend I just put a number on it and I'll put a plus number so it's takes energy to be able to lose electrons so is an author Rick the reaction of reaction in courts have now as yell is demanding electron it's clear taken electronically so that's in other words an electron affinity and once again we talked about last time and again with this kind of giving them enough so that takes a little bit of energy and so that becomes 314 marinated 340 did numbers for the specific things on his announcement that he would ever be expected in our eyes but I really want you to get out of this is the magnitudes so 1 B will go into more how to calculate energies and how to deal with them on a very mathematical form I want you kind of think about the magnitudes here so we have a plus energy we have a minus energy so we have an annual make them an axle Thurman taking on energy giving off energy of so once we do that now we switched to the electrons right we take away the upfront from what we've put it on the other 1 token 1 released energy now we have sodium chloride over it we have sodium plus in chloride minus attract each other and that's favorable to that acts of ceramic as well so we get a negative 787 so you may want had small notes serial if you've forgotten the white designated and of the mechanics of ceramic for signs pluses are an affair McManus's are excellent so in order for this to be energetically favorable you want to be acts of terror which means do positive reminded the end of make X wreck and now we want this whole thing the the axis erect throughout the whole thing tonight well what they need and we need all 3 of the numbers to add up to be a negative number so if we do that I here and we add this this and this the sooner we get negative 642 killer jewels formal so that definitely accident rate we had a negative charge so it's lower we're losing energy were releasing energy and the environment and so it's going to be stable so the idea here is that you want your electron affinity and you want in this value Cindy bigger In this 1 if this is too large for or the user to small negatively nearly very it's close to 0 you're not going to be all the form In this case would because these added to the S make a negative number so you're ionization energy has to be low enough to make this access in these have to be large enough to make it if city and these have to be with negatively large enough that any negative and not to make the whole thing now In this goes into wide of we tend only form ionic compounds with metals something needs to have a low enough ionization energy to actually be able to do this if this is too high it's good overwhelmingly if this was like to founded and then these when it went back systemic anymore when you add these women meal to get into the negative line so because of that it's typically just a matter of right think back to last classed as a on the left-hand side of the periodic table where all the medals were those were were low ionization energies were so this is where these numbers are kind of love and so these numbers are able to overwhelm and they're able to say no I don't care if you take a little bit of energy to do lost so much energy that still energetically favorable so it's mostly just medals and do this because it's metals that have a low ionization the ones on the right-hand side of the periodic table Commons accidents from flooring and although those have such a high ionization energy this number is so high and a look at it you find .period your table numbers and see there so high that the I it's it's going over well in the 2nd half but also will start symbols in America in a little more formal introduction of then I go in there and how we represent are elements when we drop em out and there's lots of different ways to represent them status symbols is 1 of the simplest and most used so if you put this symbol for the elements inside and you put your doctor on the outside so before I if a iodine for instance has 7 valence electrons tonight and all your on the course just your valence ones in whenever you need to draw bond you do a lot you'll sometimes see people represent the that instead of allowing bill put 2 dots instead and then squish them closer together like this that's fine it's not wrong in here I like to do it to show you how a switching electrons that when we talk about our bond you can see it on when you're actually drawing music gets a little bit messy and I would
suggest keeping it like this in just putting the bonds just remember that every time to draw 1 of the lines it's comprising 2 electron but so now is used to my advantage we have potassium we have died I knew going to take the electron from potassium desire which forms potassium iodide the plus and a minus charge Lewis structures get a little boring with ionic compounds there a little bit better little more entertaining to use with covalent competence when magnesium remembered this was our example worries said well sometimes ionic compounds the former one-to-one ratio sometimes magnesium might need to give an electron to 2 different Adams in order to make everybody happy so many easy as wide to electrons reindeer and Flori had set up a leveling anyone so they give 1 the fluoride and 1 the other 4 the flooring forming magnesium and the simple way of thinking about that was always what we need to balance the charges from Nona ions are we know that magnesium to class and she forgot why I'm looking appeared table in the 2nd column so you go near period table you seats 2nd column you know it needs to be 2 plus you go to Florian effectively said he will last 7 electrons so it needs to have a minus charge so now if I have the energy to plus in an effort minus the balances charges that as a faster way of looking at it now there's rejected doing that as well and it's to crisscross the charge so if you had aluminum 3 plus In oxygen to minus the take the 1 in charge in bringing down the other charges bring it down and I'll give you a neutral compounds that because 2 aluminum it's 2 times that of the 2 times 3 6 and then to oxygen so it is a very oxygen to minus certain negative 6 so plus 6 I 6 100 additional charge whatever reaffirming ionic compounds needed to be neutral charge now there is a caveat that gray and the caveat was what if you have the exact same charge of a higher number really about playing your best bet is that you have something that the 2 plus 2 minus just don't put them together you know that it's a 1 1 thing off the 3 plus a 3 -minus 101 but if you don't remember that you don't pick up on it right away and do the crisscross trick anyways Nunavut Ng 202 you have to reduce that down now remember only for ionic compounds do reduce the staff for the less you have to make an NGO you have to reduce it down that's not true covalent compounds clear come-ons might be and to H 4 In you wouldn't reduce down ionic compounds always have to be lowest collaboration of covalent compounds don't but it also wasn't clear compounds so this is when you're going to be sharing elected so for instance with chlorine you can go ahead and you can take it you can't share each 1 elect this'll share 1 of its electrons thus 1 of its electrons and your form a single 1 if you're each if each element sharing 1 electron that single bond you you can drop like this or this I highly suggest doing it this way and so that towering in the representing all along :colon compounds so they ask you draw this that's how you want to drive he was all the more complicated example where now suffers needing to share electrons with multiple Adams in order to get what it wants so it's going to when 1 oxygen to with another oxygen to form sulphur-dioxide and so you can go ahead and whenever you fair sharing for electrons total 2 from each element that double bond and so you can write it like this which gets a little messy so much for further like this and actually form the double bond now the simpler 1 jets find is kind of write them out but almost structures get pretty complicated and so let's go through some general rules and this isn't confined to keep with you as we go through all of the examples because we have a whole bunch of examples to do and will follow through these guidelines as we go step 1 and this is the stuff that when you start doing that then everybody steps and it's a terrible idea it's where you start making mistakes on the Newseum Connolly's about sometimes too and I'll have to go back and do it at the end just make sure I get it right so 1 violence electrons in the beginning this will help the started in the end will check for your mistakes so it's very important to do make Costello structure so that is you put your central added inside and the new line at you put everything else around it and just draw a single bonds you connect them together currently connect the atoms and you don't worry too much about lone pairs and in double bonds all about that just get you started so you know every time a draw line that's didn't to electrons now you're going to have similar turned left over to figure out how many electrons you have left over start with the number that you started with subtract out how many you had used to form your single bonds and now you know you have insurmountable elections but those around to where you need to put them around now were trying to get 8 so if you can get the neuron to something else so at this point you do want a honey be thinking certainly don't follow after talk about what those are all of these are some common exceptions but there's going
to be some other ones too and was have wide area minute period on a check for those who you know hey this is adamant typically does something that a little bit funny so let's go ahead and make sure that you know I I'm at least aware that it doesn't have to follow the rules media well maybe it won't now if you can't distributed electronically futile put them around music I had to and that I don't have enough electrons Woodward put a dent in the need to serve for more advanced stopping double bonds stopping travel bans on a little no 1 should good at them if you're short by 2 electrons StatsCan have done 1 more behind you short by 4 electrons you have to add to bonds so that sort of a little trick to we need it's arguing that that anyone will faster however many elections you have left opening did you missing you need 6 Republican deformed 3 now this next part and again we don't know we don't know what all this means that we're going to go through each of these in more detail on as we do the examples but this is just an inside the keep with you while you're doing these so you have you have you don't look at them and see what we do and stuck it on a hot start this problem this is your guidelines they are hard rules they change a little bit and when you're done with all that in the theoretically have everything without cuts is theoretically have all of your Adams happy now you check your formal charges and will talk about exactly what it is we want small so when we get there we want to minimize them now the only way to really do these is to go through into a tunnel examples and so that's what we're going to win it would town examples at which point will talk about formal charges and then we're going to do someone that break contact too but so the 1st I was starting out was the 1 that isn't too bad will start with nitrogen so the 1st step in this is your error checking and making sure that we have somewhere to stock from is a countervailing selections so you .period periodic table and you say Well how many of valence electrons as nitrogen have well each 1 alone has 5 so we had to nitrogen each 1 with 5 valence electrons and so we had 10 electrons we don't have a charge so have subtracting electrons and that's important nature you remember to move will do some of those later as well so our 1st ever next step then is to draw skeletal structure so we gotta do that now we need to add an electrons that will satisfy the architectural what say we try to do this with traditionally say OK well I used up 2 electrons making that bond so I ate less so why 2 OK well short electrons I can get everything architect nature then we need to more you're for more here and I can't do that certainly in the I'm not sharing enough electrons I'm short for electrons which probably than need to do to bonds as sort of a good rule in your head to think about so there's only 1 place to put those bonds is gonna put him there which means now I need have for electrons left because of 2 4 6 so I used up 6 I started with 10 so for electrons left send 9 2 4 6 8 10 always go back to the end and double-check missionary electrons and this is why it's important to do this in the beginning even once you start getting good Edelman you start just kind of whipping down at the very end if you didn't do this go back and do a real quick doubled to make sure the don't right the next 1 now we need a little bit more complicated and now we have to figure out which 1 is going to be a central atom now good rules of thumb for less and there can be more than 1 central atom as 1 of the least elector negative element that's going to be a central and everything else ,comma goes around hydrogen highway bonds is headed to so all it has failed in its ground state is as 1 ass electron 1 1 a selector and so it can only ever form 1 bond hydrogen now out of form any more than 1 by 1 and so because of that you're going to that's never going to be a central at element accident hands buttons and it usually only if it's weird things that only from 1 by so all those roles that puts carbon said but still without a prior elections so we have 4 from carbon we have to from hydrogen well what's right that's so we have 2 hydrogen atoms in each 1 of them have 1 electron and from oxygen we have sex so we have a total of 12 electrical so if a cobbler said In we put everything else around it now we try to distribute electrons so hydrogen up doesn't former hydrogen is the duet role of only has 2 electrons so we had to elections here and 2 electrons here so that leaves us with In into a trance here so that leaves us with his 6 electrons to work so let's go through and see if we can do this well with 2 4
6 8 10 12 so were set for electrons everything has not so if she walk away at this point not going to get your points In the reason to fear that will talk about in just a minute but let's furry now see if there's another way we can do it and after we talk about formal charges will talk about why 1 is better than the others said the other way that you can do this it is by doing that forming a double bonds here including you to oxidants here now let's look at all of our own architects and see what we have here we had 2 4 6 8 were dead 2 4 6 were not good and then our hydrogen they're here we have to look into occupation has 2 4 4 6 8 so were good and Alice Agha carbon 2 4 6 8 so did carbon here we don't have enough electrons to do it here we did so double bonds and trouble bonds are awaiting give ourselves extra electron because we're sharing them so the sounds wrong some of the 1 that we want to be but this example and we're doing these you'll notice I've given myself an entire she delivered that's on purpose worryingly using these for the entire year like rest of the quarter pretty much all the way up until least gas loss
so make sure that you give yourself just as much as I did in really adding to on when we get to hire only it's too John and author of holiday geometries on when we get hybridization we're going to go through empower hybridization with the bond angles will do polarity where images spent a lot of time in the sheets of paper so 1 person she is about right on any more than that we start running out of room near the end of the quarter but now the next 1 must look at the little complicated because now we have to central atoms known luckily people usually writing is in a way that makes it a little bit easier to see what's going on so You Think I see here that we have beach 3 N H 3 and has written that way on purpose you can sort of see that you have like beach 3 groups bonded to an N H 3 so 1st ,comma electrons legal abortion yes 3 Riordan nitrogen and we have 5 we hydrogen this 6 hydrants and each 1 has 1 electron so if 14 elections work skeletal structure we can kind of see that born in nature there are the only ones to conform multiple bonds so they're going to need to be bonded to each other as well as all hydrogen and so at this point we say OK well harm electrons do we have to 4 6 8 10 12 14 so we're God does everything have architect Felder for hydrogen Stewart all hydrogen the set and then boron has 2 4 6 8 the nation has 2 4 6 8 and so sector now we're we're and talk exceptional singer Borland actually 1 that a lot of times will have less than electrons allowing times had just have 6 in fine that but here's an example where it actually does would normally not most of them still has 8 the next 1 now
we need to do and I am sure you have some practice doing so we have actually asked for for last so ,comma ball electrons says Iran has 8 it's noble gas and then flooring has 78 so we have for Florence in each 1 of them has 7 so that when be 36 but it's a 4 plus charge we me that we need to take away for electrons To give us 30 to elect so the plus charge so we have less electrons than that neutral atom and so we minus the 4 electric so it's 32 electrons so we we put the gun in our center Florian never allowed to graze the cattle and will talk more about as well so fluorine is ever only gonna have 1 bond so there is a hydrogen exploring only 1 can be central so when we go through we draw these out we know flooring can have more than 1 month since it just told you so really all we can do at this point without an hour-long pairs in hope everything works it's not will have to add something sitting so if you count all of these 2 4 6 8 following around we see that we do in fact have 32 electrons so were sacked board that we don't have to do anything else earlier now are last and most complicated 1 Farina this will actually be able to finish until we talk about some other things OK so end to well so the slums kindness not as simple as the rate and will see wine and so 1st of all most elected negative element here is oxygen so nitrogen is going to be our son 1 of our nitrogen so we can set up our central Adam is being
nitrogen it was implemented in each side where it needs to be a major 1 side oxygen and the other 1 in which an draw skeletal structure now if we try to give everything architect here from 1st reading ,comma electrons so you see that we have 5 electrons from each nitrogen and we have to nitrogen we have 6 electrons from our oxygen leaving us to 16 occupants if you try to make your touch here we're just going in filling in Europe elements earlier electrons and we just enough penicillin notice we can't do it we don't have enough here we would need 4 more electric so if a short for electrons how many bounces into form need formed 2 months OK well where do we put those bonds now we have some options when we had the form to bonds with that in 2 groups we didn't really have any options so we just sort of put them in between the 2 nitrogen here we have options so I had a few bonds a need to form so I could just put 1 bond on each group I could
put both bonds To the oxygen Oregon put both bonds to the nature and and let's go through and Fillon architects at this point so we have to hear so we need to move on this nitrogen set 2 4 6 8 this oxygen needs for more we ,comma by-elections 2 4 6 8 10 12 14 16 per cent we moved under this 1 now this nitrogen needs 6 this nitrogen again as end this oxygen is going want this nitrogen needs to and as oxygen needs we go through and power 2 4 6 8 10 12 14 16 dead 2 4 6 8 10 12 14 16 were going OK well which 1 is it so all follow the roles all of them have the least elected negative element in the inside so which 1 do we do this is where the very last step on the slide comes and calculate formal charges we are 108 yet so let's let's learn how to do that and will come back so there's an equation press and once you start getting good at you're gonna want to do it more certain totally enviable to quickly check all formal charges you don't necessarily always wanted the filling into this equation but for the moment it's a good thing to start with so your valence electrons sees start their sofa Nigerian its 5 oxygen 6 furor forget his goatee a periodic table in income over until you get to the I'm element where you're at now that's your starting point then you subtracted the number of electrons that Europe and the Arab League you're talking about in whatever you're looking at what I can always think of it as which ones they actually all so which 1 they're certainly their electrons so in a way that that's calculated the number of electrons and the number of electrons are actually in that it has always itself its pairs so you're subtracting away all the electron the inside the lone pairs and half of the bonding electrons so if you have a behind 1 of those that are out of 1 of those electrons belongs to 1 element in 1 of those electrons belongs to the outlet other island so for accounting purposes you always think of the half of the bonded on Monday some examples that I make that make more sense so what schools through in a sign formal charges all the Lewis structures that we dead and then we get done with them will be a will actually go through that last harder example that we did in decide which 1 it actually it's which was Lewis structures actually correct so I just sort of starting over Lewis structures again you don't want to this quite a bit throughout this next little bit of the court but so our 1st one so what is the formal charges on each major event so we go in we say well in formal charges are going to be out on specific so it's for each added the molecule now in this case they're going to be the same but the emergence of 104 so how many electrons does nitrogen has valence electrons desire to have good pier table Yukon over his United and has 5 now you have to decide how many our it's it's all homered as it have in this part of the structure and USA Track those away so anything in a long pair is it's all so it has to from long Paris From the bonds it only gets 1 from each so 1 2 3 city of violence electrons minus-5 it's 0 so this major formal charges 0 now is the other nitrogen the exact same thing happen has fired valence electrons it has to electrons are among Paris in it's 1 from each bond and so that nitrogen plus 0 well this so now we can go through to talk about each 1 individually so let's start with the oxygen so how many valence electrons does oxygen half has 6 and units attacked away anything therein lone pairs so 1 2 and any of the bonding electrons but only 1 from each bought 1 2 so we have 6 minus 6 so the oxygen school charges 0 carbon we noted .period table we say how many valence electrons as it has and has 4 so we subtract away anything in this case is no longer here so we we'll have to count any of those Iniguez 1 from each bond so 1 2 3 4 so we have for electrons there so it's formal charges 0 now we need to talk about hydrogen hydrogen has won valence electrons and gets 1 from each bond so it's formal charges 0 as well and that would be seen at the 6 true the other hydrogen as well so that our formal charges we have next time it's another sign we go through this can be a little bit different .period actually getting some formal charges so let's start with the hydrogen hydrogen gets 1 valence electron and it was the same freedom headed and it'll get 1 from Labonte so everyone hydrogen here follow the same rules and so there aren't any plus 0 now let's talk about the board in the nature for bore on how many violent electrons as a half the good appear cable industry that has now if you come here a week on electrons known those gets 1 from each bond 1 2 3 4 so bored has a minus 1 charge now nitrogen if you go to period it but it on period table year has 5 valence electrons In Yukon around 1 2 3 4 In say hello plus 1 turned on education now this is the 9th and 10th of flora so freedom Florence because again there follow 0 Saurel you don't want biggest 7 electrons from the pier table valence electron now here each 1 of them has 2 0 4 6 better among Paris so those are the long Perez it's not sharing them it's is siding with them so it all and all of now for the bonds it just gets 1 so we have 7 valence electrons minus 6 transitory long pairs and 1 electron that is in the bond so is the Florida 0 charge knowing that it is now it's a noble gas certain that faith groups has 8 valence electrons and we subtract 1 from each bond 1 2 3 4 so we subtract for electrons so it has a plus for church so as whirling through the issue notice that were Connie electrons very differently depending on what we're doing when you're accounting for architects we counted everything right through the non-military said 2 4 6 8 0 has an architect flooring has 2 4 6 8 0 I have the flooring
has not tapped the hearing different from me to formal charges with formal charges when the bonds only call is 1 for each other so floridly only got 2 companies 1 electron for the sake of architects Yukon artist eh OK so now we can move on for a last 1 which was a bit more complicated than we were actually able to finish so we had to us and we said well I don't know which of these 3 do now we can actually go through and we can figure this out so let's do that let's call simple formal charges on everything and then there's a little bit quicker this time in doing a little bit more like how you should be doing an example of and how after me devote a week of practice in a week of homework you should be doing so we look at oxygen and we stayed home e-mail and intellectuals of oxygen well it has 6 alone How many doesn't have among parents for a case so we're down to 2 electrons at that point in into here so oxygen has 6 valence electrons interior has 1 2 3 4 5 6 so 6 minus 6 is 0 so action which could just make a little bit more no major nations has 5 valence electrons and here we have 1 too 3 4 3 of 5 minus 4 is equal to 1 it's a positive 1 now here's nation
has 4 valence Electric City valence electrons and here has 1 too 3 4 5 6 so 5 minus 6 C minus 1 so again when you're practicing at home to Italy in the beginning to the letter and doing up until now we knew gate as and did a little bit on a role that this is kind of the fascinated and this is how you want to you for the sake of you checking you work quickly without having to waste too much but the cynics 1 here we have oxygen normally has 6 valence electrons here has 1 2 3 4 5 6 0 6 minus 5 plus 1 Over here nature normally has 5 in here has 1 2 3 5 minus 4 His plus 1 here Major normally again has 5 but here has 1 2 3 4 5 6 7 5 minus 17 minus 2 OK just going there putting falters on everything in and this is going to help us decide something other down here oxygen normally has 6 now we have 1 2 3 4 5 6 7 minus 1 here need to normally has 5 1 2 3 4 4 so 5 -minus Forest 1 positive ones Over here nature has 5 valence electron in here has 1 2 3 4 5 5 minus sliding 0 now as and couldn't we need to go with this is something we you can only do in your head for everything you'd still have necessarily need to write them down if I ask you to write down the aisle list structure and you don't have to put in formal charges if you have something that's an iron actually like this if you have someone like an iron is not actually correct unless you put the charge someone but you don't have to put the Chardin xenon you can just put brackets but the charge and that's fine that's just correct something like this that doesn't have a charge you don't have to put that on you don't actually have to put the formal charges must ask for you should do it in your head anyway now we have to decide which was correct so if we look at these again check 1st is to make sure that all of our formal charges add up to whatever the charges here the charter 0 so this 1 adds that to be 0 this 1 add that to be 0 this 1 attitudes so we done formal charges correctly Donna Lewis structures correct now we have to decide which set of formal charges is the best set of formal charges and so if we go through we look we can say Well this 1 has a negative 2 0 1 0 1 this 1 has a negative 1 1 0 is a native won 1 0 discuss some really high formal charges and there's no reason for at 2 1 1 is acceptable if there is no other option but you will have formal charges of pluses for some time we saw that with the but if there is another option you want do that so going that 1 right away that one's not going to be right so now we have to decide between these 2 so they're basically the same central nitrogen has the same but now here we have a negative 1 and the nitrogen here we have a negative 1 the oxygen so we have to figure out which 1 is better so for this we a kind of backtracked to what we talked about but earlier today Alaska last we're talking about electric utilities so we talking about electric utilities were talking about the amount that and Adam is willing to pull the electron density to ward it inside the box so it's kind of act situation and something like oxygen is more elected negative and something that nitrogen so if the electron density is going to be shifted 1 way or the other it's going to be shifted so that the more elected negative elements the 1 that's pulling the electron density toward it is going to be the negative 1 because well it's that it's more electric utility it's my has more electric utility and has it's pulling those electrons toward it more it's going to take the negative charge not nitrogen so this was is going to be correct because the oxygen is more elected if there are more native so you always if that's possible and keep this in mind if it's possible you wanna put your negative charge on your most elected negative element that's not always possible but for instance this 1 again In this 1 we had a plus I wasted an right of so jobless sealed for fun sometimes draw carbon-monoxide and you see that you're you're forced to do the opposite and don't have a choice of that's your Honor choice you a choice but is only like this we do we can choose to put it on the nitrogen by drawing about way or we can choose to put it on the oxygen by drawing that way so this is the more correct way now moving a bit more
in detail operating Cabral said settled to this and talking about it and no 1 is going to be a little bit more detailed talk about exactly when we can and can't do this so the 2nd period elements there happened to this will Drexel intercourse hydrogen helium as well hydrogen helium and then lithium up through neon they're not going to do it do not ever had 10 electrons off Flory on oxygen and nitrogen and you will just get it wrong there will be no partial credit for that you just have a wrong now 3rd period and lower you can do that and it's fine that's not a big deal there's some learning to do more than others but all but now the search area Lincoln duet where the 2nd 1 can become a fact that they have and the orbital sitting right there so the deal right there they're able to be used for bonding you can use them from running on the news and for hybridization initial talk about later in next chapter of insulin anything the 3rd well below can do it secondary ones do not do it ever some of them are going to have a lot less than 8 in the half to but they can theoretically anything could have lessened it up out of the 8 electrons but that's not necessarily normal From beryllium aluminum and boron it's pretty normal if you see 1 of these and you can't fill the architect don't worry about it just move on of something like carbon and oxygen you're going to probably feel there is seldom going to break the architectural it's not something that you never see in this class of where these elements they do it all the time so get used to these elements breaking Carroll on the low side and having a laugh as far as having more that falls into the category of survival ideas these I talk about sulfur phosphorus C 9 on chlorine and that a fair amount so if anything they're grown below can do it but this is the sort of your common ones that actually do all the time so while star induce some examples of this now and then do some more next time but if so it start with assets 6 so are central 1 sulfur since we can't really do anything of the camp of foreign and center and so when we go through this sulfur here and we have 6 things so we just off input Florian In because as a list structure we need to go through any doubt in all our along Paris so we come up how electrons started with just to make sure that everything is still OK so 7 6 sulfur 7 from each fluorine and we have 6 of them so we have 40 electrons can we go through Connolly's up and added to the 40 and so were also so sulfur is an example where pay it low it it's OK with having 6 bombs and usually with sulfur you want a candidate and haven't seen while Italy there has on 2 arms and a top 10 aerial have for bonds Erickson 6 bombs in sort of configuration so Italy the act like oxygen which along the periodic table an oral form 6 the next 1 this is kind of similar to what we've done before only now it's not an iron now it's actually asked for without any 4 lost so we ,comma Pollock chance we had 8 4 9 we have 7 from each fluorine and we have for them so if 36 electron not a charge said afterward adding or subtracting any now when we go to draw list this is a good example of 1 where you can get yourself into trouble if you don't call the electrons 1st so up until now a lot of them have once you get really good at that and you may say law have become electron I know what it looks like this is 1 where you made yourself into trouble if you don't so if we go through trying to set up a skeletal structure we know flooring only 1 bond so where does colorful at this point you might be tempted to say OK everything not that I'm In which case should get it wrong and all the other questions following about bowel and had later the hybridization of geometry and bond angles and things like that so we look at this and say OK how many electrons have we used up if we come we only use up 32 3 2 on former electrons that we had to deal with so we can't put those electrons and Flory story only gets to have xenon can have more if need be so we're going to give so that gives the 9 moreover it has 2 4 6 8 10 12 election so that's OK so that's what we're getting is the 9th 12 elections and saw breaking the actor there we can't break it was flooring busy and to break it it was not the Palestinian
3 so he added by electrons we say Well we have 3 from war we have 3 from each hydrogen 1 from television so we it's 6 electrons .period we got a job there and we have this and at this point there's nothing else we can do we only have 6 electrons to work with all of really have 6 electrons total there's absolutely no way to give Borland 8 weekenders make 2 electrons out of nowhere so we're not that's all there is to it literally do anything now as good outside practice on this was very popular all formal charges we haven't done any formal charges yet because I haven't really come we've had an option where we needed to decide between things but it said it's a good practice to go through and make sure that you can do it in the habit of doing it and so there's lots of places here from the practice no more complicated ones in these once tend to get people off for all these Polly atomic ions we return so-called obsolescence soul and in this case this 1 would be called sulfuric acid so off forecast their carbonic acid any of you want to get in the habit of knowing so the general way that these look like because otherwise you might be tempted to take sulfur and bond that once each oxygen and wanted a to the hydrogen and don't wanna do that whenever you see these you need to know that these hydrogen actually bonded to the oxygen so when we going do this what if a sulfur in the center Oregon put for oxygen is around In the hydrogen is gone oxygen and that she just you should know that as part of your skeletal structure and from now on in a few company later and say Well how was I supposed to know that .period years so this is how you not for in this goes for sulfuric acid carbonic acid any of those OCS so now let's go through Weidenfeller actor in here because it is not only much else elsewhere probably do with oxygen you at this point in practicing may get in the habit of saying OK well I know oxygen pretty much always has to but to Bonds song is going to give it to abandon its on Paris now if we add an hour electrons and we try to add 2 for 6 years into for 6 years will see that we can't do it in so what we need to do will see that were short for electrons solo home practice and do it you'll see were short for electrons so we need to borrow and so we're going up there to balance here the there to on Paris here and to on Paris here and natural finished now you'll notice I forgot to add in all of my electrons and make sure that we have the right amount so let's do that real quickly just as the double check if you forget to do it in the beginning especially when you get good at you may get out of the habit we forget just do it at the end of the show that you're right and when you go through and do this system we do have 32 electrons and we are all set so at this
point we have gone through down a bunch was a break world we have a bunch more that we're going to do his Lewis structures are really really important and will not nearly all the rest of the material for this chapter and Chapter 3 and Chapter 5 if you can do is to remain a bunch more examples next time on you go so will just kind of go through them at that point and keep going through and get into all of that so cruel and therefore a today and start upon the rest of the next day


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