okay so actually in chemistry we are interested mostly in electrons why because electrons take part in chemical reactions and um it's extremely important to know where electrons are inside our atom and it happened that they have their own places and place decide what could be property of atom but to tell the truth it's not like certain place where Elton sitting we have probability of finding electrons actually it was guy whose name was sure younger who decide to film errors who decide to find out where is place of electron and he he created very complicated equations and he solved these equations because he was genius mathematician and genius physicist but you know what he only found that we cannot know exact place where electron are but we can find probability finding elephants and actually Solutions of his Urban Schrodinger equations are electron orbitals so electron orbitals are probability of finding electrons in a certain region in space and also directly from shirodinger equation three quantum numbers derived and these quantum numbers are n which is principle quantum number L which is angular quantum number ml which is magnetic Phantom number and later one more quantum number was added Ms which is spin quantum numbers this one two numbers four of them sort of like address of any electron in atom so knowing these four four numbers for each electron we can know where this electron is okay so for now we just know that some guy solved equation and found probabilities of finding electrons and this probability are orbitals and also three quantum numbers derived from his equation now let me let us talk about this quantum numbers in details first of all here is Big Picture hierarchy of quantum numbers can you see that principal quantum number can be like 1 2 3 4 I can tell more four six seven and if you look at periodic table just a second [Music] table can you see that here we have period one two three four five six seven so one two number n principle Phantom number is about periods in periodic table so we will see very very shortly that all beetles and quantum numbers are connected mirrored with periodic table um and can you see that a Quantum principal quantum number somehow connected with angular quantum number is blue and um this blue angular quantum number somehow connected to its magnetic uh we will return to this big picture now let us talk about each Phantom number in details first one is principal quantum number it specifies size and energy of orbital um so in chemistry actually size and energy is pretty much the same say we have orbital s if we have orbital One S and let us say we have orbital 2s you see that I draw orbital 2s bigger bigger size and bigger energy smaller size smaller energy so I can tell you that something that has Quantum principle quantum number one will be lowest energy and any level higher will have bigger size and bigger energy and also what we see on this picture so you see that it's shown like like levels level number one or shell number one level number two or Shield number two and so do by the way uh I used word still and level these two words can be used interchangeable some textbooks use shell some level and I noticed that I change sometimes this one or other okay so principle quantum number tells us about level shell and I add or period period number one period number two three and so do one okay next is orbital angular momentum quantum number shortly angular quantum number this is l okay uh angular quantum number tells us about shape of orbitals I give you very simple analogy principle quantum number can be thought as Street and angular quantum number can be thought as house so shape of uh orbitals or shape of house and what what shape of um orbitals are possible it can be s orbitals and and S orbitals looks like looks like sphere and we call it sub shell yeah yeah you see that if principle number walls was about shell angular quantum number was is about subshell or our shape can be this ma the the can look like this um if I want to look at this shape more specifically you will see that this shape is consists of three orbitals one looks like these second look it's like this and sort like this if we put them all together we will receive B sub shell and P sub shell looks like all three combined another type we have d sub shell I tried to draw it somehow like this for sure you will see that it is more complicated and uh also we have F sub shell for these sub shells angular quantum number can have special special values if I say that L is zero I mean that I am talking about s uction or S type of house let us say if I have L which is one this is p sub shell if L is 2 I'm talking about G's actually in just another way to say this option means L equals two and a four F sub shell L equals three you might ask do we have other numbers then 0 1 2 3 yes theoretically we can have two um Infinity but in periodic table we have this number of elements that only these sub shells can be filled so uh and let us look at hierarchy if I have principle one to number one which means shell number one shell number one has just one subshell it's like on street number one only one house shell number two has two subshells sn2p shell number three has three subshells in Surprise shell number four four sub shells 4S for B for d for s for or F so can you see that it's pattern one shell one sub shell shell number two two sub shells shell number three three step shells shell number four or sub shells okay let us move to the next quantum number it's magnetic quantum number magnetic quantum number ml tell us about individual one orbital now we look at these orbitals which orbitals do we have we have S orbital and you know what sub shell S Sub shell s for which l equals zero for which angular quantum number is zero has just consists just of one orbital it's like to say that house Type S has just one room consists of three orbitals look at this my sub shell P consists three orbitals my three orbitals look somehow like this um in this picture you you see something like this but I can I can draw it like this it's the same it's the same and if I have something like this it's the same so in a lot of textbooks you will see this kind of AIDS okay a sub shell D consists of five orbitals here five orbitals are shown they are pretty much this shape I will show you my drawing so something that is shown here looks somehow like this like two eights together and sub shell F consists of seven orbitals again let us look at this pattern sub shell is one suction p three subtial D five sub shell F 7 orbitals okay and here is big picture principal quantum number which is shell then angular quantum number which is sub shell and then magnetic Phantom number which is orbital orbital kind of rule so it's like Street house room okay uh what are values for ML if we have only s orbital magnetic quantum number will be always zero it can have value zero if we are talking about suction peep you see perceptual p three orbitals are possible which are shown here can you see that in drawing here I showed like three boxes very often because I don't want to to draw these eights all the time very often are so implied boxes each box represent any one orbital and um four these three orbitals my number will be negative one I mean ml number magnetic quantum number zero plus one I always start with negative zero in the middle and then positive when I have d sub shell my five orbitals have m l numbers negative two negative one zero positive one plus two and if I have sub shell F my magnetic quantum number are these green numbers you might notice that on this picture I also have some designation some here I have p x p z p y here I have D X Y here I have d x in power 2 minus y in power 2 here even more complicated something this is other awaken how I can distinguish between different orbitals and I can tell you that these numbers do not relate to these numbers no relation it's just other way to show so if I have orbital with Magnetic quantum number negative two I have no idea which one okay and and we don't need this I guess um quantum number is quantum physics they are needed there from shared in the equation so this designation and this designation not very non-correlation okay now last quantum number last quantum number is speed actually scientists noticed that electron can be thought as small magnet so um in magnets they have such um such a property which is called spill spin means that if I speak this way I have let us see uh spin plus one half or I spin this way I have spin negative one half it is no noun that electron is not bull and it's not spinning but still it's very um convenient to call this property spin so magnet stink quantum number Ms can have just two values plus one half and when we write like this we show it as Arrow up or negative fun half and then we show it's like spin arrow down and if we have this orbital we show our electrons if we have two electrons in orbital like spin up and spin down by the way I will tell you in advance that no more than two electrons are possible in any one orbital so you see that here only two electrons can be present one okay three no four no one or two this orbital two electrons are possible with different speeds okay next piece of information so so far what do we know we know that there are some numbers four of them uh next I want to introduce term the generate orbitals the generic orbitals are orbitals of the same energy so look at this if I have here I have S orbital it is lowest energy it cannot be dictionary because it's just one only but if I look at my three be poor beetles which are shown here B orbitals they are the same energy they are the same energy we can say that they are degenerate how to understand it say that you came to Hotel B in an Hotel P you have three rooms and all these rooms are they cost let us say seventy dollars each one the same price the same energy so they are degenerate they are the same if you look at Five D orbitals they are also between themselves they are degenerate it's like you came to the hotel in all five rooms are the same price let us say one hundred dollars identical price identical energy that is why 5G orbitals which are shown here they generate we also have let us say seven F orbitals between themselves they are degenerate it's like if rooms which have the same price let's say 150. that the same energy degenerate okay next piece of information I know it's a lot of information but um after I introduce this information we start solving problems and all this stuff will be absorbed by your head so don't worry power the principle okay first I um give you information about this policy principle and then explain in simple words what does it mean principle says no two electrons in an atom can have the same set of four identical quantum numbers so four quantum numbers it's like in group print of of electron like a address of electron so you know that we all have our I our ideas our unique let us say others so but what does it mean for us if we have one orbital I can have two orbitals or I can have two electrons on orbitals but they should have two opposite speeds why it's so imagine situation if I have one orbitals and two electrons would have spin one spin up this means that they have the same n the same L the same uh M ml because they are on the same orbital and can you see that even m s will be the same so if I have situation like this my electrons will have four identical quantum number and this is impossible because of power principle that is why situation like this not possible situation like this not possible also you see that I cross out spin down also in quantum physics there is some principle that when electrons build up in atom they want to have highest possible speed so first if electron is alone it will have spin plus one half so it Arrow up okay now let us start some example list the value of nlml for orbitals in 3D subshell okay 3D first let us talk about principal quantum number principal quantum number so what is it three so because we have 3D this first number tells us about principle quantum number let's read okay now next L is angular quantum number L can be zero one two or three and 0 means sub level S one means sub level B two means sub level D and three means sub level f do I have d sub level what is my l my L is two so all the time you have something you need to write like 0 1 2 3 and um on the bottom 0 is 3. so where to find information we just did this it's here it's here so in this table okay so z l zero is s is one is B and so do okay if we are talking about sub-level D it can have five orbitals and I will show my five orbitals with this nice and simple boxes so these five boxes represent this sub level d sub level I could show here um so I mean these orbitals but I'm not going to draw these orbitals I just draw these boxes and my ml which is magnetic quantum number remember my in the middle will be zero always and I always start with something negative so negative 2 negative one plus one plus two so possible m l for 3D orbitals can be negative 2 or negative one or zero or plus one four plus two so those are possible magnetic quantum numbers if I am talking about any electron one which which is on 3D sub-level okay now yeah sub-level subshell is the same you see I use it interchangeable probably I think I use level and sub level more but okay now you do B so what we we're talking about was a now do B please do it by yourself I Do by myself try and we compare results and okay let us check results so uh we have 4B pretty easy to deduce that m one to principle quantum number is four now I have p so my angular quantum number can be zero or one or two or three because I have P my um angular quantum number is one and when I have P orbitals there are three T orbitals on um B sub level that is why I draw this three boxes my zero will be in the middle it will be magnetic quantum number I start with negative one and I finish with positive one so ml can be negative one or zero or plus one that's does it make sense let us move to the next what is the total number of sub shells shells likes houses are associated with principle quantum number three can you answer so if I have Street number three level number three how many sub levels okay let us let us look at our big picture if I have shell number one shell number one has one subshell number two two sub shells shell number three three sub shells shell number four four sub shells so if I have shell number shell number three how many sub shells three uh and my three sub shells will be three s three B and 3D okay so this was like my a now B what is the total number of orbitals and orbitals is about a ml about magnetic one two number associated with principle quantum number n equals three more than seven okay let us do like this when we have n number three we have and and this is shell we have subshell uh three s three s looks like this it has one or D Tau it also has three B three B has three or B tells it also have 3D and 3D has five one two three one two three four five or B tells so all together how many orbitals do I have nine I give you shortcut by the way there is formula number of orbitals and uh on on some on some shell will be this quantum number in power two so you see I wanted number orbitals on shell number three so it will be three in power two it will be nine does this make sense so you can have formula or you can deduce you have all information so you see you have big picture you have it from the beginning so look at this I show you so we just did it we are here this is our shell those are sub shells and those our orbitals one two three four five six seven eight nine okay tell me if I have n equals four how many orbitals do I have 15 so you see 4 in power 2 is 16. but let us count one plus three plus five plus seven it will be sixteen okay let us move to the next uh question what is total number of electrons associated with principal number n equals three do you remember I told you that maximum two electrons are allowed on one any one orbital it's like orbital is like small room only two people can live in this small room so in in this one only maximum two electrons possible so my question is how many electrons can leave on this nine orbitals eighteen perfect so if I have n and three maximum 18 electrons can occupy this okay I know that I spelled it not correctly okay occupy them okay now your turn if I have it was a now I have B I want to know if I have N4 what is maximum number of electron electrons quietly do it by yourself I Do by myself okay okay okay do do we have answer what is not maximum number virtues perfect so um on level number four maximum number of orbitals and we just did will be n in power 2 will be 4 in power 2 will be 16 or B tells team rooms and each orbital can have maximum two electrons so 16 multiplied by 232. 2 it's like Let Us return to our you see that here we proved that on level number four we can have a 16 orbitals and each one can hold two electrons are we good with this does it make sense okay let us move to the next problem yeah and by the way here is shortcut I sh I showed you the electron capacity so it's 2 multiplied by n in power 2. okay next which quantum numbers and remember we have four quantum numbers principle quantum number angular quantum number magnetic quantum number and speed quantum number which quantum number or numbers relate to a electron only and I'm sorry ML and this is MS so this is principle this is angular this is magnetic this is spin which one related which one or within seven columns relate only to electron this guy is only about electron it can it can have values positive one half over negative one half and it tells us if our electron has been up or spin down so only steam number relates to electrons all others principal angular and magnetic tells us about orbital and look at this let's let me repeat this information because this information is important for us principle quantum number tells us about size and energy of orbital so if we have one know that this orbital small and energy is not B if I have one to number four I know that my orbital anyone but with score will be big and a lot of energy angular quantum number tells about shape of orbital and shape can be this one this one this one or that one and a magnetic quantum number tells us about orientation in space of orbital so you see this plus three about orbital and what does mean orientation in space look at this you see that all my P orbit orbitals technically the same they are like kind of eight but if it's like this it it p x so it has this orientation or orientation can be like that or orientation can be like like this different orientation so [Music] um quantum number MML tells us about orientation of forbidden okay let us move to the next next piece of information is home's rule it's not hunt he's German guys so his name is hold whose rule tells us let me read this and then I explain I open simple words whose rule stays that if two or more orbitals of equal energy are available and orbitalsophical energy means degenerate orbitals electrons will occupy them singly before feeling them in pairs what does it mean let us say that you came to Hotel p and in this hotel all rooms are the same energy they have price 70 dollars and let us say that a lady on reception told you that room number negative one is occupied by one Stranger by some electron and she says give me seven seven seventy dollars and you can live separately in the Next Room number zero or you can live for the same number of money with some stranger do you live with stranger or by yourself what is your choice by yourself electrons will do the same then person number three will occupy also room separately but person number four if no other rooms possible the only possibility okay no choice I will live with stranger but we will sleep like this not like that okay so um whom through tells us that first they do occupy so if empty room empty orbital is possible electrons first occupy these orbitals like separately okay let us the first electron in an orbital will have spin plus one one one half after all the orbitals are half filled the electrons start to pair up the second l or electron on in the orbital will have spin negative one half okay and if there are two electrons in the same orbitals the spin opposite direction okay let us move to the next piece of information write the four quantum numbers for all electrons in 4D orbitals I noticed that it will be better if I have I'm sorry I couldn't do this but I can I will take some more space for me okay how to solve problem like this where probably I will draw first of all I have 4D orbitals my 4D orbitals looks like this like five one two three four five boxes because I have five G orbitals and uh electrons which are possible on these orbitals can be shown like this one two three four five six seven eight nine ten and to distinguish between them I assign some numbers like one two three four five six seven eight nine ten I want to tell you that these numbers have no physical sense I just rolled them to to distinguish between my electrons why because I want to show what are quantum numbers so I create table and in this table we have principle quantum number ambular quantum number magnetic one two number spin four electron number one two three four five six seven eight nine ten nine ten okay first of all for all my green electrons what will be n what will be principle quantum number four because they are on they all of them are on 4D sub-level so four four four four four and so don't okay now my angular quantum number can be zero or one or two or three zero means s um one means B 2 D and 3F I see that oh my green electrons are on 4D sub level so what is L what is angular quantum number for all of them it will be two yes so now I know that talking about magnetic quantum number my box which in in the middle will have magnetic quantum number zero and I start negative two negative 1 positive one positive two okay could you please tell me what is magnetic quantum number ml for first two electrons negative two so I will write negative two negative 2. tell me what are spins for these two first electrons first one up is positive good good so we have positive one half negative one half very good okay now what is ml for electron three and four negative one so negative one negative one and what are spins for number three spin positive one half and four four it's negative one half very good now what about electrons five and six what is ml for them zero and what are spins for number five positive one half and negative okay so please complete rest of it by yourself complete for seven eight nine ten and I can play by myself we check results okay in let us check results it makes sense it's pretty logical if it makes sense please do the same for 4B for 4p I want you to draw these boxes and then table like we have here okay try foreign okay let us go through this together I have 4p I if I have P my P sub level consists of three orbitals you can you can look at big pictures so you see that any B sublevel consists of three orbitals that is why I should show as three boxes okay and in three boxes maximum number of electrons which can be here is is a six so I have six electrons because they they they both they all of them are 4p my principal quantum number for all six electrons will be 444 and principal quantum number now about B about B so can you see that angular quantum number is one when I'm talking about B that is why my L for all these six electrons will be one okay and then talking about magnetic quantum number ml it is always something that works which is in the middle always zero and I always start from negative and finish with positive so I have negative one zero plus one are values of mlml is magnetic quantum number so my first two electrons one and two has magnetic Phantom number negative one and still this will be plus one half minus one half three and four will have magnetic quantum number ml zero and Spins up and down my electrons five and six will have magnetic number one to number plus one does it make sense okay uh no is it okay I clean up we we just some stuff will be missed okay so did did you have time to copy okay I just want to yeah to do something like this now you know what to talk about talk you about we talk about quantum numbers about orbitals now you can ask me why do we need this stuff because this stuff relates to periodic table you know the table as we see this it's not just random it depends on properties on inner structure on delicate structure of each atom so these orbitals actually dictates shape of periodic table but before we talk about this in details I want to introduce one more rule we call it bow principle if I remember correctly of bowel can be translated from German like in order maybe somebody speak German okay still it still should be like in order um okay so it's not about Farm probably so what does it mean this means that um in the ground state of an atom or iron electrons fill Atomic are orbitals of lowest available energy before occupying higher level what does it mean so if I have let us say and number one and and number two available and I have one electron my one electron should occupy lowest possible level before occupying second when only all the places at level number one occupied only then next electron can move uh anyhow and um the rule is that if we are talking about and one and two three higher number means higher energy so n equals seven for sure is higher than n equals six and if we're talking about sub levels are sub-levels S Sub level if we're talking about the same level we'll have lower energy than p B will be lower energy then F and D I'm sorry in D lower energy than f so f is most energetic um also what we see here is order of sub-level feeling so I try to show like two diagrams together let us try to look at this so actually item pretty much looks like town so look at this this one is nucleus we're not interested in nucleus in nucleus we have protons and neutrons but we are interested in electrons and electrons outside so look at this first we have level number one red then we have level number two orange and this level divided by two sub-levels 2s into p then we have yellow three level three and level three is divided by three subletels three S three p Three G after that we have green um level level four by three days here we have all we have three B after 3p we have four yes the only then 3D is how nature looks like so sometimes levels even over overlap it's okay okay let us move to example number nine and this example will will show us how good we understood as bound principle Okay so for the given atom what is the order of increasing energy so please do A and B by yourself I Do by myself it's it should be pretty easy let me okay and one lowest energy and seven highest energy and yes lowest energy F highest energy let me show you um yeah probably probably okay let let us focus on green on this green look at this I don't know which something like this okay can you see that uh something here is 4f something here is 4D something here is 4p and something here is 4S if we focus just on 4S 4p core D and for f it is clear then 4S has lower energy 4p has higher energy for D has even higher and for f higher okay okay good good let us move to the next piece of information now what I showed here is periodic table but yeah by the way do you want to have small rest before we continue because it will be okay so I just what you see here what you see here here is periodic table which shown order in which orbitals are cute so I told you that we have S that we have P that we have D and F now look at periodic table first I have just level first level and in first level I have just one sub level and this sub 11 is 1s then I have level number two and in level number two I have two sub levels 2s and 2B by the way do you remember that sub level P consists of three orbitals and three orbitals can have maximum six electrons because two electrons are allowed at which orbital let us count how many to P elements do we have one two three four five six do you think it's coincidence no so it's kind kind of one t orbital second p orbital and third p orbital okay so level number two has two sub levels two s and two B okay then we have level number three level number three consists of three s three p and here is three d 3G yes if you remember probably you remember that can you see that um my electrons my sub levels My Level sub levels can overlap so yes we have like uh three p three p then we have four S in 3D but still my three three level numbers three has three sub levels okay this is not all now let me show you level number four has four sub levels let me show them 4S then I have 4 p then I have four deep and four f or F you see so in periodic table we have like periodic table is mirror all these orbitals um two um No Electronic structure is extremely important for us why because electronic structure or how electrons occupy levels in our atom dictates what are chemical properties of certain atom very convenient to pay to show how electrons occupy this level is electron configuration and so electron configuration is way to pres to represent precisely the electron Arrangements in atoms okay so what is what in here um electron configurations looks like one S2 or something who is who here one here is actually principled quantum number or shell s is about angular quantum number or about subshell and this superscript in this case two it is number of electrons on certain sub-level we also should know what is abbreviated electron configuration so sometimes you you will see electron configuration and you have this bracket and then break it you can see some Noble guess what are our Noble guesses neon argon Krypton Xenon radon I don't know what is it it's something new those are radioactive and maybe maybe two three five atoms exist so who cares but um when we talk about noble gas this means that our shell is completed if shell is completed we can put it in bracket um okay let us let let us work with electron configuration first hydrogen what is the point of the healing or like the noble gas being here why you will see in a second it's because but I explained because think about this if I want to write configuration for Saloon it will be long like very long so to make it shorter I need to write abbreviated electron configuration and I will prove it in couple minutes okay so let us do examples so first Hydrogen hydrogen has atomic number one atomic number one this means it has one proton and by the way one electron so for hydrogen my configuration will be one is one who's who here one is my sub level one s in hydrogen in helium lives in in this sub level one level number one it's level number one consists of one sub-level so um okay and by the way I show my orbital diagram so you see just one electron is here then I have example Borum Warren is here Warren is here so can you see that boron has five for atoms and five electrodes so let me show you we we can use this big periodic table but we also can use this one for drawing configurations any time I start I start from the beginning I start on hydrogen okay Boron is my goal so I start one is two two first electrons of boron are here on level number one then I have 2 s how many one two so I have two s two these two electrons live here and then this sub level is to B so this was 2s this is 2p so I have 2p how many electrons live here one so look at this two plus two Plus One will be 5. so what I did I wrote configuration and in this configuration I showed where my five electrons are I'll rewrite it here one is two two s two two b one okay and I want to show you an orbital diagram where I am so first two electrons one is two second two electrons two is two in my uh two P I have just one electron here okay let us proceed to nitrogen my nitrogen is here and I start from the beginning foreign has seven electrons so one is two this is covered then I have 2s2 this is covered after that I have 2B how many one two three so look at this 2 plus 2 plus 3 will be 7. so here is where my seven electrons are let me rewrite it here one is two two s two two B three so two electrons are here one is two then here two is two and then I have three remember if three guys leave in hotel P they will live separately that is why I have to write them like this if they pay money they want to live alone not together because they are strangers okay now let us talk about uh yeah in nitrogen pills about oxygen my oxygen has eight electrons again I start from the beginning so now I'm interested in oxygen and my oxygen is here here so I have one is two this is covered 2s2 this is my 2s sublevel then I have 2p how many four one is two two is two two B four and if if I want to draw up down up down one is two two is two and then look at this here I have four so they will occupy like this three separately number four should live with somebody else so it looks like this then I have uh fluorine nine okay please write a electron configuration of fluorine by yourself all you need you are here you need periodic table that is it Try by yourself I Try by myself okay okay with this now I didn't tell you about abbreviated how to write abbreviated look at this let's start from flooring I won't abbreviate it or floor you let us say that I have piece of paper and I covered my flooring like this what Noble guess can I see just above hilu so helium will be completed shell so I write helium in this bracket can you see I covered pouring and I can see noble gas hilum above so what do I have after hilu after he yes after hilu I have two s two and two P one two three four five so this is my abbreviated so actually one is two is hilu hilum two is two two B five and here abbreviated will be hilum two s two two P four here abbreviated will be hilum two s two two e three here abbreviated will be hilum two s two two b one no abbreviate is for hydrogen okay now Neon please do neon by yourself I Do by myself it has 10 neon is here do electron configuration in latest check results see everything okay so can you see that it's completed shell so we have one is two one is two two is two two P six and abbreviated can be shown like Helen 2 is 2 to P6 or it can be shown like just neon just like this and here I'm my orbital diagrams all electrons are paired okay does it make sense about electron configurations we will practice and it should be absolutely easy for you because it's no question should I do should I know how to do this or not all of you have to because this is our tool we're going to use it for all other stuff uh probably in basic chemistry you learn about um this um configuration and you had no idea why you should learn this now in our course we are going to use it yeah by the way let me show you valence electrons valence electrons here will be outermost so okay uh these guys are valence more specifically this and this these guys are way less so actually everything that is after Noble guess if I'm talking about representative will be violence so this valence this valence so Bay lens weylands electrons are important because they take part in chemical reactions so we have four electrons and valence electrons it's like saving account and like credit card credit card like valence electrons you use it every day to buy some stuff food gasoline whatever you spend money all the time those are well and cell phones and let us say you have save an account and you never touch it now let us move to the next selenium and let let us write a I am going to do it here with your help okay to be clean and nice selenium is here I start from the beginning so I have One S two and this cover helium hydrogen and hilum after that I have two s two and this covers listen and birilu after that I have 2p how many 2p6 this is 2p 2p6 now I am 3s 3 is how many two perfect after this look look at this I moved to this is 3p 3p how many six after that I have four S four S how many two now attention can you see that we have these guys copper and zinc ten of them those are 3D guys so ten of them 10 of them five orbitals five D orbitals you see so they are completed so we have 4 d how many 3G 3G 10 3D 10. and after 3D we have um three e four p and four P how many one two three four so we have four B four so okay here is my configuration write it down um um okay I will rewrite it here one is two two is two two b six three is two three p six four is two three D then four p four now let me show abbreviated configuration okay if I won't abbreviate it what I do I will cover my um selenium like this what Noble guess can you see just above organ so that is why my abbreviated configuration looks like Argon and after yeah and after argon I see that I have four S two three D ten and four B four let me write it here Argon yeah it probably it will be easier if I show you like this so something like this is argon argon A4 S2 3D 10 4p4 what are my valence 3D not valence if something completed forget about this so let me show valence valence are for s two and four p four six of them valence do do you mean 3D no no 4S you said that yeah because as isn't it but still our selenium will use this can use this in reaction S and P even if as completed is still a count which you can use okay okay so you will see this all the time okay and we have one more and this guy is here it has pretty name dimu who named this okay let us write electron configuration together it will be long one it will be good practice okay our final is here um we start from the beginning one is two okay these two guys covered after this after this we have two s how many covered then we have 2p 6. these guys covered after that we have three s how many two covered after that we have three p how many six covered after that we have four S two these guys covered after that we have three D how many tenth covered after this we have 4p how many six after this we have five is how many covered after this we have 4 d how many 10. after this look at this in June antimony tellurium so this is five P so five b how many six so covered okay just a second because I want to write here I will make more space for an author I just want space too yeah okay after that we have 6s how many 6s2 now attention you see that something should be here and something that is here is 4f it is clear here so can you see that after 6s we have 4f so this big periodic table show you that after 6s we have 4f you see 6s then we have 4 F and only then we have 5D okay so we have 4 F and you see that our guy is here it is f element 4f how many three four F three so this is does it does make sense so this is our whole configuration it's long one that is why we need abbreviated how I can write abbreviated if I uh let us look my element which I am interested in is here if I cover it if I cover it what never guess can I see Xenon so my abbreviated configuration looks like Xenon after that I have six s two and four F how many three can you see beauty of electron abbreviated electron configuration lazy I I think now you understand why we need it so this periodic table works fine um but if if we need something that is um like here it's better to use this one so here can you see that we really can see on this periodic table which sub-level is first which is second I showed you here I created it just recently for you so you see one is after that we have two as then we have 2B and so do so you clearly see that after 6s you have 4f okay nice let us move so I want you to write down here let us move to the next piece of information yes sure yeah by the way I need to give you some more information something that I showed you are configuration that obey rules some elements to note a beiru rules and they and they have their own exceptional configuration in our course I will show you just two exceptions and I will show you today and we need to know to memorize just two exceptions all other configurations which I am going to ask you in this course in our class will follow the rule so if you have periodic table you don't need anything else you can write down any configuration you see it's pretty easy you just follow that is it don't agree with me that it's easy Okay so Isabella can I continue yeah um next task is electron configuration of cation and anion okay first one is okay it's not pretty I will do something like this reload so first one is sodium so sodium one is two s three s so I have one is two um should I write abbreviated let us write abbreviated what should be in my square bracket for sodium neon and afternoon I have what 3s1 perfect three is one now if I want to write electron configuration of sodium Plus what should happen with my neutral atom sodium to create sodium Plus what should happen with 11 electrons my sodium should be looser it should last one electron so actually electron configuration of sodium plus is identical to configuration of neon so it so configuration of sodium will be Neon or if you want full configuration to 1 is 2 2s2 2 B6 so this will be configuration of neon and this will be configuration of sodium Plus okay now fluorine uh we somewhere here we already wrote configuration of fluorine is here okay so it will be 1 is 2 yeah we won't abbreviate it helium two s two two B five okay what about F minus my fluorine is here just second I'm going to show you this pretty atom what should happened with atom of fluorine to which has nine electrons to create F minus should gain one negative charge and can you see that when it gained one negative charge it will have configuration of neon so it will be one as two two s two two P six not two P five because it had five P electrons and one more electron will be added so it is neon or one is two two s two two b six okay calcium abbreviated configuration of calcium I need your help so my calcium is here 4S and could you please tell me what noble gas should be in this bracket organ because if I cover calcium all I see I see Argon so I have Argon and then I have 4S how many 4s2 4s2 Forestry so my calcium is organ or S2 what should I do with calcium neutral atom if I want to create calcium to Plus I should remove two positive two negative charges good lose two electrons can you see that my calcium when my calcium will will will will lose two electrons it will be as good as argon it will have configuration of argon so I can write down that my calcium 2 plus is argon or if you want um it will be Neon um three is two three is two three b six we can write like these two okay uh now please try to complete oxygen oxide aluminum aluminum Surplus and nitrogen nitrite by yourself configuration I Do by myself and we compare results foreign okay so oxygen is hilum two is two two before so oxygen is here so hilum uh two is two two P one two three four oxide or to minus means I need to add two additional negative charges to my oxygen so instead of 2p4 I have 2p6 and this is electron configuration of Neon because so oxygen if I add two more electrons I will be Neon okay aluminum aluminum has configuration neon three is two three p one let me check aluminum is here you see that a neon is noble gas which is above and after that I have 3s 2 3 B 1. if I want to create aluminum 3 plus this means that these three electrons this one and this this two and this one should be removed so my aluminum three plus is just Neon nitrogen is helium 2 is 2 2p3 nitride can be created if I add three additional negative charges to my nitrogen neutral atom when I do this instead 2p3 I have 2p6 and this is configuration of new by the way now I think it's pretty much clear why atoms create an ions orchest ions they want to be as good as noble gases noble gas configuration is stable everything in science in chemistry physics tries to be stable means lower energy so it's like probably it's clear if I stay like this [Music] pull down but if I lay down it will be the lowest possible energy if I low if I lie down I cannot fall so okay let us move to the next piece of information let us so by the way are we okay are we good with um fetides and anions what I showed you were Elements which are representative let me once more time to remind you what representative elements means so one a two a three a four a five a six a seven a eight a they are representative so actually this representative and these guys representative um D elements and F elements are transition elements they are not represented okay so now we're going to talk about electron configuration of transition elements and transition elements cations here you will something will be different and by the way here we learn about two are exceptions okay so first one first one is scandium kingdom is the element and it is here so remember we have one two three four S and after four S we have three D so our schedule is first 3D element I'm going to write immediately abbreviated configuration if I cover my skin Doom what Noble guess can I see Argon so we have organ after argon I have what four S two covered and then I have 3D how many 3D one so um Argon four S two three D one now yeah and by the way our orbital diagram is shown here now let us talk about titanium for titanium it will be argon 4S to 3D how many two perfect three Argon four is two three D two for one medium I have argon four S two three D how many three perfect now for chromium it should be for chromium it should be 4 is 2 3 D4 if chromium is decent guy it will be its configuration but it is not he's not she is not whatever chromium is our first exception instead of being like this it will be 4S 1 3 D5 it will be organ 4 S 1 3 D5 here is shown its orbital diagram can you see I have four S one 3d5 why it's so weird why this guy is so weird okay I will give you explanation and the explanation is half healed three d sub level is energetically favorable let us write this down half filled a 3D sub-level is energetically favorable if you think about my explanation you will understand that it explains nothing it's just statement scientists don't know why it's this way okay actually probably I I put it different way scientists scientists still argue why it this way but it's for sure it's energetically favorable but they don't know why it just statement that if energetically favorable that is why chromium exists like this but I wanted to figure out so I from the library I took some scientific papers and there were a lot of equations with um differential equations and a lot of factors so it was a big article I couldn't I couldn't after couples pages I understand that it's too complicated it's because of quantum physics maybe couple people in board the board can explain why but it should be very Advanced physics and very advanced mathematics for us if an exam I ask you why chromium is so weird and why chromium has this configuration your answer should be half field 3D sub-level is energetically favorable period okay let us move to the next guy manganese manganese has organ 4s2 3D how many one two three four how many d okay okay it will be four S two one two three four five manganese will be five three D five then we have I run organ 4s2 3G how many six Cobalt will be Argon four S two three D seven nickel will be argon four S two three D eight now copper is next exception if it's decent guy and follow all the rules it should be I'm talking about copper ah four all right so three okay four is two three D nine but it doesn't want to follow the rules and it it has configuration for S one three D ten four S one three D ten and you see copper is here explanation completely filled three d sub level is energetically favorable it explains actually nothing if we think about this but this explanation is good enough for us so let us write this down ah completely filled 3D sublevel kill any sub level is energetically favorable okay and then we have zinc which is argon 4S 2 3 d10 good now about ions here we have weird situation and we need to memorize this so can you see that we have 4S and 3G first electrons which will be removed because our Italians are losers so how cation can be formed our atoms should lose some electrons first electrons to go will be S electrons so for schedule it's pretty easy when um when these electrons and these electrons will be removed because I need to remove three of them I have my skin juice replaced so actually skin tone 2 plus scantium 3 plus is just argon nothing else because 4S 2 and 3d1 gone okay titanium three plus first electrons to go attention these two and one more electron will be gone from 3D so titanium three plus is argon three D one not logical not intuitive memorize three plus first electrons to gun will be 4 S so I have Argon three D okay how many 3D how many y two two electrons gone from 4S I need I need 3d3 good good now chromium three plus I have Argon yes this was oh let me see let me see maybe so it's vanadium one two yes my dear friends sorry let us yeah so 3D sorry so yes you're right and here will be two so chromium three plus plus electrons electron to go will be four S1 and are three and two more will come from D so we have three D how many 3g3 manganese first electrons to gun will be 4S so we have Argon 3D how many five yes very good now I run two plus would you please tell me what will be Iron 2 plus 3D how many okay I run three plus Argon 3g5 good good good Cobalt two plus okay do rest to feed by yourself I Do by myself okay we compare results prettiest because we hobo two plus so just four as two electrons should be removed a nickel also two plus so four S2 should be removed in case of copper two plus one four S electron will be removed and one electron from D orbital should be removed so I have three D9 okay are we okay with this ah do you want to smallest so we completed page number eleventh page number 12. we have some example here and oxygen atom has total eight electrons right first right electron configuration of oxygen electron configuration of oxygen is One S two two is two two B four how do I know I look at my periodic table my oxygen is here so I have 1 s 2 2s 2 2B 1 2 3 4 2p4 okay now B complete orbital diagram anytime they tell you about orbital diagram by the way I don't remember if I mentioned this orbital diagram is these boxes each box represent one orbital and can you see that here it's shown the right way how it should be because we have like energy in energy on one of one s is always lower energy 2s will be higher energy 2p will be even higher it will be up up oh next orbitals will have higher energy but let us write these um electrons so one is two I show it like this then I have 2s2 and then I have 2p4 okay one two three and four comes here I completed I completed a orbital diagram so this is actually my b this was my a now they want us to write Oak one two numbers for all these electrons for convenience I will count them one two three four five six seven eight I want to point I want to tell you that these red numbers have no physical sense they are just to distinguish between these skeletons and you see that here I also have one two three all of them so um let us look at these first two electrons what is principle quantum number four one and two one because I have one s does it make sense then L my L can be zero one two or three only these four numbers are really possible and zero means S Sub level level and three F so for my first two electrons what is l zero because I I work with One S One S my first two electrons on One S okay now ml ml tells me just about orbital if I have one s all possible numbers just one possible number zero s orbital has just one ml possible and this is zero so ml for both of them will be 0 0. because it's 1s orbital because it's s orbital okay and what about speeds of first and second and this is orbital one is okay now please do two s only 2s for three and four by yourself I Do by myself I want you to just complete this this okay foreign sub-level if it's 2s sublevel my n will be two because it's S Sub level my L will be zero because it's s sublevel my ml will be zero and because 1 is up one is down I have plus one half negative one half does it make sense is clear y m l zero because uh we have we have something like this when we have let me scroll up they always scroll can you see that our ml is something that is shown in green when we have S only possible ml will be zero forever any s m l will be zero I have t 3 ml possible negative 1 or 0 or plus one and zero always in in the middle if I have D my ml can be negative 2 negative 1 0 plus 1 plus 2. 0 will be in the middle if I have sublevel F my m l can be from negative 3 to positive three zero in the middle that's it okay so now I ask you please complete this table for these electrons for 2p so for electrons five six seven and eight please do it by yourself I I Do by myself we compare results try correct or not correct don't don't worry about this but try your very best done or done and okay later us talk about this okay my 2p to B has n two that is why five five six seven and eight electrons have a principle quantum number two okay now 2p my P should have angular quantum number one that is why here will be one one one one my electrons five six seven and eight leave on sub level B my electrons five and six lives in room number negative one so my m l is negative one for electron 5 and 6. one has been up plus one half one half spin down negative one half then talking about electron number seven it will look live in a room orbital which is zero that is why magnetic quantum number is zero and spin up when I live alone I'm always up and then my electron number eight in room or orbital with Magnetic quantum number ml plus one and spin up does it make sense okay in exam what you will have something like this I give you configuration or I give you orbital diagram like it's shown here and um I will do something like this something like this and show me four quantum numbers for this electron which is circled and you need to tell me that all I need to one zero plus one half or not zero not zero I I'm here so it will be negative one negative one zero plus one so I won just four numbers this will be your answer so you will be given orbital diagram some electron will be rounded and that is it as a rule students are okay with this problem and we will do more practice okay um are we okay with this can we move to the next piece of information Okay so next piece of information we already talked about this a little bit let us repeat this stuff we have if electrons another word for inner is core electrons something that in inside like saving account and we have outer electrons okay how can I find outer electrons easy a highest principle quantum number so for example remember when we wrote this configuration can you see that 2 and 2 highest quantum number because okay here is look at this this is one two and two so high quantum number two so these three electrons will be Outer Outer electrodes so outer electrons are electrons which have highest energy level and inner electrons are those electrons which we have in common in previous noble gas like argon helium or something like this if we have completed d10 or completed F14 those are also inner core electrons but if we have completed yes completed s those are not core electrons because s electrons are always valence electrons which are going to be used in reaction okay so for now we know what our inner core and outer outer highest n inner Noble guess completed D and completed f also we need to know what is valence electrons valence electrons have different rules for representative elements and four transition elements for representative elements easy for representative elements uh they are outer so for example if I let me return to this my Borum is representative so outer electrons which are 2s2 and 2p 1 automatically well and symptoms but if I have d D element transition element my valence will be outer and and D which is not completed okay maybe it it can it can uh sound like too complicated let us do examples you will understand that this is pretty much indicate uh easy okay indicate inner outer and Valence okay silicon my outer will be 3 is 2 3 p 2 how do I know because 3 is highest principal quantum number and one is two two is two to P6 will be inner let me write core and uh it will be the same as by the way it will be the same as Neon okay and what are valence valence are outer outer and Valence will be the same okay let us do next example I have germanium so okay my um Outer Outer electrons will beam four s two and four P two outer why because highest M can you see that I have four and four what are my inner electrons 3D and all these guys will be inner my outer is the same as valence because if D completed if D completed nowhere else they are not violence okay now next one titanium titanium is D element okay first of all which are which are uh outer outer will be 4 S2 which are inner inner r those are which are valence and now look at this valence will be 4 S2 and 3D 2. why because can you see for transition my valence will be outer which is 4s2 plus any D which are not completed okay so please try to do zinc robot and potassium by yourself figure try to figure out which one is which and and we compare results okay let us check results and ask me if you have if you have any questions outer 4s2 and they will be valence core um 3D 10 also core because you see according our rule if we have d 10 completed it will be called electrons four Cobalt outer 4s2 why it's so because outer has highest reusable quantum number and Valence yeah who outer 4s2 valence will be outer and not completed 3D and poor will be something like Noble guess Cobalt my Noble guess will be Argon and for my potassium outer and Valence the same do you have the same any questions on this okay let us move to next yeah I remember that in one piece of information I I just introduced some term and I never explained this and it was like um ground State okay I don't remember where it is now I explain you what is ground State and by the way I explain what is excited state so ground state is like normal state for any electron like when I have just normal mood I'm in ground state but if somebody will come and say you know what you want one million dollars I will say great I'm in excited state the same with electrons look at this let us say that I have electron this green guy is electron which normally is In N number one lowest possible level ground stay so you see it it just circling this orbit let us say it's ground normal state when I say that this green electron won one million dollars or speaking scientific language we gave some energy some magic kick to my electron it gets excited and it can jump to higher level and jump to level number two or level number three it depends how much energy I give to these green electrons but you know what excited state is not stable State I cannot be like oh like this for a long period of time I can be excited for a minute or so after that I return to my normal ground state the same will be true for electron after a while you see excited electron jumps to higher level energy but after a while my excited electron returns to ground state when it returns it emits energy so this is how things look like okay let us read this in the ground state all the electrons are in the lowest possible energy levels when electrons absorbs energy it enters a the excited state the excited state is any state that has higher energy than ground state an electron can stay in excited state cannot stay for a long time only for short time after Showtime electron returns back to its ground state so look at this this diagram perfectly show what ground state looks like and any excited state excited state it's any level Which is higher higher than normal okay please uh try to complete example by example 12 by yourself I and and then we go through the solution together did you find correct answer intuitionally okay let us say you don't know it's okay what is it what is correct answer okay C yes yeah okay so let us look at strontium I see that my last electron obstruction last one will be at level 5S because you see and and abbreviated configuration will be chromium or Krypton okay Krypton 5s2 so this will be last okay I see that c tells me about principle command to number six for sure six is higher than five so this means that electron jumps from highest possible for ground electron level 5 somewhere higher so for sure C is not normal the cations that would then be strontium minus one okay time always positive always or sorry um it would be an extra no because you've got here you're on six so you have an extra one so it would be and it would be negative one I I'm not adding electrodes here electron here just jump from from this level to higher level to six but it's not I'm not going to uh remove electron forces I'm adding or taking away they're just moving okay that makes more sense the number of electrons will be the same okay it just just let us let us say like this we are here and this is our ground level I'm excited I know I jumped I jumped on higher level then I jumped but the number of people number of electrons in this one the same if I jumped still here okay so if we have other number of electrons never change they can jump if they are excited good question okay so let us move to the next so yes further away exactly yeah and actually if I give it too much energy it can jump to level number seven if I give it too much energy it can go away forever and I will receive good time then so actually it's possible to remove remove it forever and I will have guitar in them good good perfect let us move to the next piece of information I need to introduce two terms paramagnetism and diamonds by the way die means to probably it will help you maybe not okay ignore it so what does it mean if we have maybe yes maybe um if I have diamagnetic atom what what makes what makes it diamagnetic if I have electron configuration and in this electron configuration all my electrons are weird in other words if my all orbitals all orbitals are filled by two with two electrons such an atom will be diamagnetic diamagnetic atoms will be repealed from magnet for example if I have atom which is diamagnetic it will go away from magnet if I have at least one electron which is unpaired we call it unpaired spin because what is this this electron but this spin up or down if I have at least one it's paramagnetic and paramagnetic attracted to magnetic so this is a different okay so atoms with unpaired electrons paramagnetic diamagnetic pair yes I think the diagonal will help you that die means too so can you see that if I have two two two two two it's diamagnetic and it repeats from the field okay let us do some example um first one for sure together each of the following electron configuration first question is represent an atom in excited state okay how to solve problem like this if you have questions like this on exam we already took couple minutes before that ago that number of electrons stays the same electrons can jump but number will not change so all we need we need to count these electrons okay so what I have here I have two plus two plus six plus one plus one so okay 10 12 correct so I see that I have 12 electrons but 12 electrons means 12 protons in 12 patterns what is this guy okay this is magnesium and my magnesium now they they won't need to write ground state configuration for magnesium ground state normal so it will be one is two two is two two P six three s two look at my mechanism 3s 2 this one is normal ground stay so look at this what happened with my magnesium when it has excited one out of three is two electrons jumped to higher level and higher level here is 3p1 so all I did I count my electors I figured out that I have 12 of them 12 of them magnesium and I wrote down normal ground electron configuration now they ask me diamagnetic or per magnetic so look at this I have one S2 2s2 2p6 and 3 is 2. diamagnetic or ferromagnetic diamagnetic perfect let us do one more together and one will be just yours um let us count how many electrons two two six will be ten do you agree with me uh then I have two six two twenty twenty four twenty five twenty five electrons 25 protons 25 is manganese so I have manganese my elements is manganese okay let us write down normal ground configuration one is two two is two two b six three is two three b six four S two three D five what is not normal about my excited so 35 so you see that my manganese has one two three four five three D five in my excited electron configuration what happened one out of five electrons one of five 3D electrons jumped for higher 4p level so what this is what happened okay and now they ask us paramagnetic or diamagnetic I can actually look just at this last so I have 4 S and I have three D one two three four five because I have 5G orbitals so 3D it will be one two three four five okay could you please help me diamagnative or paramagnetic absolutely correct because five unpaired at least one unpaired at least one and pair already permanent video okay so please do last example the same way by yourself I Do by myself can not done okay what is it purple again but who who is our element perfect you're smart elements you you're smart elephants okay yeah I calculated that I have 17. now ground normal configuration I can uh write orbital diagram just for last so I see that I have fun five one is unpaired paramagnetic that is it okay uh letters so it's very good we covered we actually covered very big piece of information let us move to the next one we have okay we have like a couple more minutes so but do you feel excited that one two physics and periodic table they are related so I think it's beauty of science okay and now you know what in periodic table we call it periodic because it has periodic relationships uh so let us write electron configuration for uh for some elements within the group okay hydrogen is one as one listen will be uh listen will be hilum 2s1 sodium will be a neon 3s1 will be hilum 2s2 magnesium will be Neon 3 S 2. to s two two b one aluminum is neon three s two three B one then I have carbon which is helium 2s2 P2 silicon Neon three s two three p two nitrogen is hilum two s two two B three phosphorus is neon three s two three p three oxygen is helium 2s2 2B 4 and sulfur is neon three is two three B four okay two two P five and a new one three is two three B five and One S two one okay illum two is two two b six knee in Neon three is two three b six okay can you see that if you look at a electron configuration within first three periods you can probably notice that my valence electrons are very similar outermost valence electrons and those are out those outermost electrons make elements within one group to have similar chemical properties and this is like Central Point in all chemistry similar outer electron configurations correlate with similar chemical behavior I know we are tired but we have like five or maybe 10 more minutes I start I explain you some term shielding effect and I will I will start my next lecture from for from this again but still I don't want to um lose time okay I need to introduce some term and this term is children effort first I ex first definition effect is decreasing of attraction between nucleus and outermost electrons due to Inner which are core electrons okay we have no class a nucleus has protons we can think about nucleus as magnet magnet can be strong for weak but it's magnet and we have electrons so this yellow guys which are shown here are electrons but you know what electrons in atom can be found on different levels level number one level number two level number three and so don't and look at this electrons which are closer they feel very strong attraction to nucleus and electrons which are further from nucleus they feel attraction this blue arrow shows attraction but they also feel repulsion with electrons which are kind of between nucleus and and themselves and because of this repulsion effectively these guys feel less attraction to the nucleus I give you analogy let us say we have mama and mama has three kids one kid is baby three months and uh two other kids five years old and 17 years old for sure mama loves attracts all her hits the same it's for sure but she spends more time with baby because baby needs her at the moment and kid who is 17 and even younger who's five or some something else effectively like Mama laughs love them less it's not true but they feel because this baby have like scream it effectively repulse they improve mama and this is children effort baby is Shield inner electrons shield for outer electrons outer electrons feel less attraction because of shooting effect okay what we need to know about children ever just last piece of information if we go who provide these children effort inner electrons inner inner inner guys so when I have like shell number one cell number two shell number three so for a electron which is on shell number seven all previous shells six five four three one will be like Shields from the nucleus so if I go down there group children effect increases so this um this if I have electron which is here it has more shielding effect than any electron which is here if I have baby five-year-old and 17 year old 17 year old experience greater shielding effect because between him and mother two other kids baby one should and five-year-old second shoe five year old kid has just one shoe baby so he heals kind of more love more attraction okay so this is what what does mean that shouldn't efforts increase if I go down there group if I move across period shielding effect the same why because look at this for example for Warren for carbon oxygen core electrons will be hydrogen in helium so they have the same shielding effect core electrons level Shield level or shell they provide shooting effect okay probably will stop just here