How to Write Electron Configurations and Orbital Diagrams (General Chemistry I)

how's it going guys in this video we're gonna go over how to write electron orbital diagrams and we're gonna go over a whole bunch of tricks to kind of use the periodic table in order to kind of find your answers so really quick first we're just going to go over this which is super important to know the s orbitals all contain two electrons and when you're writing out the actual box diagrams it's just going to be one box each box will have two arrows indicating two electrons the P will have six or three boxes the D orbital will have ten and the F orbital will have fourteen electrons so seven boxes he's having two so you technically if you have access to the periodic table don't even need to memorize this because you can check it out right here so for the for the s orbitals other than this very first one you can kind of break it down to this column each of these has two and this is the S orbital right here now over here we have the p orbital everything over here and again just if you disregard this because that's one s two you have one two three four five six and then you know each of these is your p orbitals you can think of it that way you don't have to remember the six you can just remember three boxes each with two arrows here and then the same thing for the D it's just going to be this section here and then for the F you know and this is ten and these down below have 14 and it's gonna have seven boxes because that's the F orbital so that's kind of one way to to think about it I think that the the less you have to memorize the the easier sometimes you can kind of like focus less on rote memorization and more on the actual technique and the kind of the procedure of how to do these problems so first off we'll start with a really straightforward one just nitrogen so this one we're going to start going through and I can do it on the periodic table and then move back from there we know nitrogen is right over here so we're going to be in the first p orbital so nitrogen is going to be 1s2 2s2 and 2p3 so there's a couple ways you can go about this one way is you can just look at you can you can count these up so two four five six seven and look at the atomic number nitrogen is 7 you can either work forwards or backwards there so if you want to take the the atomic number and then just keep writing these until you reach the the amount then you know do math along the way that's one way of doing it another way is to just look again at this we know that the in nitrogen ends in the p orbital and it's the third one in so it's going to be 2 P 3 and then just work up to that so now we'll do this with the boxes we have the 1s the 2s and the 2 in the in the 2p so however that 1 2 3 so in the 1s we have up arrow down arrow 2 electrons in the 2's we have up arrow down arrow and then in the 3p we have up arrow up arrow up arrow and that's going to be like the picture diagram or the you know the box diagram to thing on what they call it and now we're going to start going through to a little bit further down the periodic table we're going to do magnesium but before we go to that one I want to share one other little trick that I like to use with these problems makes it a lot a lot easier in my opinion so if this is something that you're able to draw out then it might be really useful to you it's just 1 s 2 s 3 S 4 S 5 s 6 X 7 s and this is mirroring the periodic table in the order we write them in so 1s 2s 2p 3s 3p 3d if you take one of these images and you make diagonal lines like this might seem complicated at first but once you once you find like once you use this in a problem you'll see that this really drastically simplifies how to look at these problems and the more you can simplify it I think that the the less mistakes you're likely to make so again that might seem confusing on first glance but I'll show you how it works on this magnesium problem here so first off magnesium it has an atomic number of 12 and we're gonna go into it like that but say we don't even want to look at the periodic table we just want to look at this and we want to get to 12 that way first of all we know that it's 12 so here we go we're going to start with the 1 s 2 and then follow the diagonal line so next we're going to go to the 2s to get to the end of that now start at the top of this one 2p6 3s2 and there's magnesium right there so in that case we just once we get to the end of the arrow we start at the next line and the next line the next line it's going to get really hit really helpful for the later ones and I'll get to that in just a moment so for now we have the one us the 2s the 2p and the 3s we have up arrow down arrow up arrow down arrow up up up down down down up down alright great now we're just going to keep going through and in the meantime I'll try to keep both of these in the end of you if I can all right so now we're going to move on to number three silver we're gonna be quite a bit further down now and like I said there's a bunch of different ways we can go into this now you can you can just count as you go or you can use this chart but basically I like to kind of just start counting up until I start to get close 1s2 2s2 2p6 3s2 and if you get lost you can just reference this the rest - now I'm going to start at the top of this 3 P and then 4 s 3 P 6 and then we're you have 3p6 4s2 I'll start on the next line 4 s 2 we finished that line that we go to the 3 D 3 D 10 because like we said there's 10 electrons per D orbital so we just got 2 3 D 10 for p6 for p6 then we have 5 s 2 and then we complete with 49 because silver if you block out this section here it's 1 away from completing the next D orbital and and I think usually you won't have to draw out the box diagrams for all this but just for the sake of anyone that wants to practice I'll go through it really quick 1 2 3 that's the 3s 3p 4s and the D 1 2 3 4 5 boxes 3 D 10 then we have the 4 p 6 5 s 2 and then we have the 4 D 10 and whenever we're doing these we know we can fill everything except for the last orbital so just up down up down up up up down down down up down up up down down down up down oh and we're just going to keep going through like that and then for this last one we just want to count to 9 so 1 2 3 4 5 6 7 8 9 so we're just missing that one last electron and yeah that's silver they're going to keep going here we're going to do uranium and I think if you were to try to practice these other than just making the electron orbital diagram for every single element are like skipping and doing a various ones throughout the periodic table I think that the best way to practice or get quickly good at these is just do a single electron orbital diagram for an element that's way far down on the periodic table such as in this case uranium which the atomic number is 92 and then we're just going to go through it and in this case with anything that's that far down in the periodic table that's when this chart here will come in handy so let's just start start going through it so 1s2 2s2 2p6 3s2 3p6 4s2 then they have 3d10 and say we get lost here 3d10 we just follow the red line for P 6 5 s 2 4 D 10 and we're just gonna keep going we're at 40 10 5 P 6 6 s 2 4 is if we have 4 P now so that's 6 s 2 4 F that will be for F 14 5 D 10 6 p 6 7 s 2 and now that we're getting close we can start to count it out we're at 7 s 2 and then uranium is the third in on the second F orbital so that is going to be the 5 F right there because we just finished the 7 FM at the 7 s then we go to 5 F 3 and that's uranium now this is probably a good time to demonstrate the shorthand formula basically how it works is you just jump from the the nearest noble gas so for eg for instance silver is here and we're just going to jump to the most recent previous noble gas which is in this case going to be Krypton so over here we can call this Krypton I'll say or Krypton and then move from there so Krypton will be its one it's a the 2 P 3 P 4 P 6 so we'll just find that over here for P 6 and then we're going to keep going so 5 s 2 and then for d9 so the K are in brackets 5 s 2 49 is considered the shorthand formula now for uranium we'll go in and do the same thing since it's we have to kind of watch out for these stars during a Nima's on this row where 90 is the starting one so it's going to be this row here on the periodic table which means that the shorthand formula for uranium this is going to be RN for radon 7 s 2 v f3 picking up right from there okay great so there's only one other thing I think that's probably necessary to go over really quick I'll move these out of the way just to get a little bit more room sometimes you'll get electron formula problems where you have to do charges so we'll just go through a couple really quick like CL minus is kind of like a common one that's an anion and basically what that means is as I'm sure you might assume chlorine is here if it's a minus charge that means a gain one electron so it's going to have the same electron formula or electron orbital diagram as argon in this case so basically what we're going to do is draw what we have for chlorine and then just add one electron so that's going to be 1 s 2 2 s 2 2 P 6 3s2 3p6 not too bad and finally we'll wrap up with this one see we have aluminum 2 plus so what does that mean if the charge is a 2 plus we've lost two electrons which means that instead of it being like aluminum the electron orbital diagram is going to be that of sodium we just move two elements down so although this is aluminum it's a cation that we have the in identical orbital diagram to na so we're going to just look at na 1s2 2s2 2p6 and 3s1 and yeah that's that hopefully you guys find this beneficial that this chart here like I said I think it really helped me my professor would routinely put like one question on quizzes or exams that would just be an orbital diagram something really far down and it's just it's just good if you know how to do the ones that are really far down you'll be more than comfortable solving the ones that are higher up and same thing with charges it's just something good to keep in mind if shorthand if you're allowed to use it it definitely comes in handy because you can imagine how much I had to write here compared to here if you can use it it's it's a great asset to have so yeah hopefully this helped someone

Channel: Med Science Streamlined

Views: 89,610

Keywords: chemistry, general chemistry, gen chem, how to, tutoring, electron configuration, electron configurations, orbital, orbital diagrams, box diagrams

Id: -nn6sc6k2Qw

Length: 16min 0sec (960 seconds)

Published: Wed Nov 13 2019