Atomic Structure part 29

Added: 2026-05-12

[00:00:00]now the third quantum number is your magnetic quantum number magnetic quantum number denoted by the letter m we can say that we have learnt principal quantum number we have learned azimuthal content number now magnetic quantum number principle quantum number we have got the information about the cells in azimuthal quantum number we got the information about the sub shells which are present inside the cells we can say that now we will study about the magnetic quantum number now how we got the azimuthal quantum number i studied from the stark effect similarly what is the main effects is that when you place an atom in a magnetic field it splits up into finer spectral lines all right i said is the main effect when you place an atom or the source producing the spectral lines you place in a magnetic field then under the influence of the magnetic field it splits up into finer spectral lines because of that which is otherwise known as z-man effect all right which is otherwise known as z-man effect from there only we got the idea of the magnetic quantum number so what is that when an electron is uh what you can say in an orbital motion around the nucleus it generates an electric field audit when electron is moving an orbital motion around the nucleus all right it generates an electric field you know that charged particle so it is going to generate an electric field electric field in turns gives rise to magnetic field got it magnetic field in turn it gives rise to magnetic field the electric field you've read it in physics all right you'll take a solar line and if you pass current through it then what you find it waves as a magnet you get the north pole and the south pole of the magnet you have studied in physics isn't it solar light solenoid if you take a solenoid and if you pass electric current through it through that particular solenoid then you find that a magnetic field is being created how do you come to know if you place ah if you take a magnetic compass and bring it near to it you will see the magnetic compounds deflects such that one end is a north pole and the other end is the south pole you have studied this thing now the reason is you can ask me that why on passing electric current magnetic field is created this answer is very simple because whatever the number of electrons is entering in one end listen carefully the same number of electrons is living through the other end due to which the total charge on that particular what you can say wire is zero it is neutral because what are the electrons is entering suppose a battery is there whatever the electrons is entering the same number of electrons is leaving through the other end so the total charge in that battery is zero it is neutral all right now when you touch the battery you don't get because it is insulated but it then you don't feel that particular thing but due to this effect magnetic field is being created because every atom is what you can say having dipole two poles are there i already said you earlier i have discussed earlier this thing it has got two poles what is that one is not poland on this some port so when you pass electric current it sets up previously it is arranged in a circular manner but when you pass electric current it sets up in such a manner so that one ends as a strong north pole and other end behaves as strong so let us say this one is there and here the dipoles are arranged in a what against a circular manner due to which it gets neutralized not south now south it is arranged in this particular manner all right we are already in physics this all these things this is south this is north again this is south it's arranged in this manner inside a particular substance a magnetic substance i mean to say got it a wire a copper valve there is also as a magnetic substance iron moves as magnetic substance so when you place when you pass current through it you know what is going to happen this circular one now this is neutral when you pass current through it what happens is that when uh when you pass current rate it just opens up this chain such that one end is not another end is out in this way not south not south and this way it will be arranging it such that one it beams as a strong north pole other end behaves as a strong south pole and in between what is that south and north is there so m hence in a magnet always the magnetic power are concentrated on the poles magnetic power is not considered in the middle you can check it also if you bring some iron fillings it will stick to the end of the magnet not in the middle you can check it got it so here why it is not magnetic part is not concerned because both the poles are present here south and not it is cancelled the effect is here is not cancelled got it now in this way so when you pass electric current what happens is that eventually a magnetic field is being set up all right magnetic field is being set up so which can interact with the external magnetic field that is earth's magnetic field we consider it which can interact with the earth's magnetic field thus under the influence of this external magnetic field the electrons what you find is that of a subshell can orient themselves means arrange themselves in certain preferred orientation in certain preferred what you can say shape they arrange itself when you pass electric current down magnetic field is set up this magnetic field interact with the earth's magnetic field external magnetic field and hence the electrons what happens is that they move in different directions and when they move in different directions they arrange themselves in such a manner they arrange themselves i am saying you that's the preferred orientations by which they will be stable minded always all right clear they arrange themselves magnetic field in this way after subshell can orient themselves in a certain preferred what you can say region of space around the nucleus what is that called us it is known as orbital what i was talking to you the electrons moves in different directions in a certain certain preferred or what you can say ah orientation of space around the nucleus what is that known as it is nothing but on s orbitals because that is the definition of orbitals orbitals are the three dimensional region of space around the nucleus where the probability of finding an electron is maximum that's it the electrons is moving where the probability of finding an electron is maximum that is nothing but an orbital in this way number of orbitals you are getting it we've already discussed about it number of orbitals we get it because we can have number of orientations the electrons ah which is moving around the nucleus all right now all these preferred orientations gives rise to magnetic quantum number so magnetic quantum number listen carefully determines the number of this preferred orientations that is in one word i can say it determines the number of orbitals in a particular sub shell it determines the number of orbitals in a particular sub shell alright i hope you understood that how this magnetic quantum number is set up again i repeat when you pass electric current through it eventually magnetic field is set up this magnetic field comes under the influence of the earth's magnetic field and hence the electron moves in a preferred orientation a preferred direction and a setup its own what you can say there is a region of space around the nucleus they arrange themselves in a preferred orientation in a preferred space around the nucleus what is that known as that is known as orbitals so magnetic quantum numbers determines the number of that preferred orientations around the what you can say nucleus which is otherwise known as your orbitals we can say that clear in a given subshell so hence what we can conclude that we are having atom inside the nucleus already studied that atom consists of nucleus around the nucleus we are having shells inside the cells we've got the subshells and inside the subshells now we came to know it is orbitals it is nothing but your orbital so orbit are situated inside the subshells so as sub shells depends upon the shell l max is equal to n minus 1 similarly magnetic quantum number the number of orbitals mighty quantum number gives you what orbitals about the orientation of the electron in a three-dimensional space which is known as what orbitals so the number of orbitals we can get it which is otherwise known as magnetic quantum number listen carefully the number of orbitals which is known as mining quantum number depends upon sub shell which is m is equal to two l plus one what i said m means the number of orbitals we can say in a particular sub shell so sub shell depends upon shell orbitals depends upon subshell so hence m is equal to two l plus one but the value but the value of m this is number of orbitals separately i am saying you number of magnetic quantum number number and no anyone dr number but the value of m ranges from plus l to minus l the value of m ranges from all right let us say l is equal to zero so m is equal to what 1 0 means assumption on it so if n is equal to 1 l is equal to 0 means first shell contains one suction which is assumption and how many orbitals one orbitals m is equal to one you put the value here l zero you get it what m is equal to one now what is the value of this particular uh magnetic quantum number minus one minus zero the value of m ranges from plus l to minus l so l is zero here so minus zero to plus zero what is minus zero what is plus zero minus zero capcom zero plus zero in general zero zero is zero so hence what the value of m is also here z all right yes now n is equal to 2 l is equal to 1 0 1 i'm not writing l max here mind it i'm not writing l max so l will have to already have discussed one is s another is p so for s m is equal to equal to 1 for p m will be equal to 2 in place of l you put it as 1 2 into 1 2 plus 1 3 ok here the value of m will be zero already i have told you plus zero to minus zero plus zero minus zero over zero is zero so it is zero but the value of m here will be there are three magnetic quantum numbers we got it now three magnetic quantum numbers see you see here that is the first shell sorry second shell contains two suction one is assumption and there is p subject now s suction contains one orbital p sub shell contains three orbitals p suction contains three orbitals all right now what are the three orbitals the p sub shell contains so that is we get it from the valley the value of m ranges from plus l to minus n so what is value of earlier one so it will be plus one zero minus one see one two three see three sub three orbitals you got it now what i said this m stands for number of orbitals number of orbitals so how many orbitals you got three orbitals so what are the three orbitals plus one zero minus one values are 1 0 and minus 1 got it in this way similarly if n is equal to 3 l will be 0 1 2 s p and d so s means again m will be equal to one p means m is equal to three d means m is equal to five so there are five magnetic quantum number in this option five magnetic quantum number that is five orbitals are there in this option all right so what are those values the value will range from plus to 2 minus 2 because l value is 2 here what i said plus l 2 minus l so it will plus 2 plus 1 0 minus 1 minus 2 okay so in this way we got it plus 2 plus 1 0 minus 1 minus 2 okay fine so in this way that is if n is equal to 4 then l will have 0 1 2 3 now you can find it out all right now you can find it out so 0 1 2 3 means 0 means assumption 1 means p substitution 2 means d option 3 means absorption correct absorption so s sub shell will have one 90 quantum number one hour vital p sub shell have got three orbitals this option has got five orbitals when i say n that is n four l can be l will also be three are you following when n is 4 all right let me rub it then this one okay not for me if n is equal to 4 l can be 0 1 2 3 maximum value is 3 but minimum value 0 1 2 so what is that s p d and f s already we have write it m is equal to 1 here i am not put anything otherwise you think it is a minus sign so here that is m is equal to what is that three here m is equal to five here m is equal to how much seven or not two into three six x plus one seven so the value of a value of what you can say this particular magnetic quantum number will be that is nothing but plus 3 2 minus 3 plus 3 plus 2 plus 1 0 minus 1 minus 2 minus 3 counting one two three four five six seven so sir it is here it counted see what i said five one two three four five so it is five simple now question is how many electrons are present in an orbitals two two always two electrons all right in an orbital maximum number of electrons in a particular orbital is always two we can say that maximum number in an orbital minded this is two minus two will come to know in the next quantum number we will come to so maximum number of electrons in a given orbital is always two two electrons are being present so in this way you came to know so now you will see the shape of this particular what you can say orbitals will see the shape of the solvents already i said you s sub shell is spherical p sub shell is dumbbell d subshell is double temple exception we do not know the shape it is complex in nature all right let us see the what you can say uh shape of the different orbitals because structural is spherical only dot spherical means just a circle all right t substitute dumbbell and double double let us see f we cannot draw it because it is complex in nature all right so now let us take here let us take here n is equal to 2 just now i said you l is equal to what i said 0 1 just now i said s and p so l is 0 means m is equal to 1 and this one is m is equal to 3 the values are minus 1 0 plus 1 so what is this sub shell is p substitution so p sub shell has got three orbitals what are those p x p y and p z x y z because electrons are present in a preferred orientation orientation means they will be arranged in a particular shape so hence what it can be p x p y p z let us see the shape of this p x p y p z all right now here any one can be x y z now here i've taken minus one in your book you might be seeing that plus one is px or in some other books you'll see zero is a px any one any value can be taken as x y z any value mind it there is no hard and fast rule that minus 1 means it has to be px 0 means it has to be y no any one you can take it all right and understood your second shell consists of two suctions 0 and 1 s and p which consists of what you can say ah first sub shell that is s structural consists of one orbital and p sub shall consist of three orbitals what are the values minus one zero and one what are the designation of those orbitals p x p y and p z now what is the shape of that p x p y and p z that is what i am drawing here see we are having three axis isn't it this is your generally we take this is y axis this is your z axis and this is your x axis but in chemistry we have nothing to do with the coordinate axis of mass nothing to do any one i can take x y and z that also let me tell you any axis i can take this also x i can take this also as x and this also has x any one i can take it x y and z we have nothing to do with the coordinate axis of maths but nothing so i will you'll see that i am going to differ in some places so don't get confused there is x looking sometimes he is writing this as x alright so do not get confused so this is your p x got it because this is i am taking this x axis this is your y sorry this is z or y and z anything y to confuse you this is y and z we can take it now this is your shape of the p x orbital similarly this is the shape of the p y orbital p y because this is y let us say i am taking it this is y i can take this also y what is the problem x and z so this is your p y this is your p x the shape of the p x you can see already i've written it here p x all right so in this way next is your p z this is your t z if i take this as a z axis y axis and this is your x axis this is your p z so this is the shape of you know this option is double so just double check so this is your px this is your py this is your pizza you'll say no sir i'll take this as a y you take now who is telling you not to take and this is your p z we can say that these are the shapes of the different orbitals of the p sub shell we can say that p sums these are the shapes of the different orbitals of the p sub shell all right similarly we are also having a shape of d sub shell which i am going to come to the next but not f f is complex okay