Atomic Structure part 22

Added: 2026-05-14

[00:00:00]now after the failure of the bohr's atomic model all right but let me tell you uh here i'm using the word failure but actually both atomic model you'll be seeing it that in the quantum atomic model will be using it once again but leaving behind certain facts like we will uh will not consider atom to be two dimensional we will not uh we will not consider what you can say about the hydrogen particles only we will go beyond that also we will also consider the xenon and the stark effect we'll consider it and we'll move forward all right so hence i should say that both atomic model is not completely discarded but the concept is discarded given by god what was the concept given before it was discarded that atom is nothing but two dimensional and electrons is moving around the atom with a fixed amount of energy which is stationary electron is not stationary energy stationary with a fixed amount of energy all right clear and it has it has got a certain fixed number of electrons in a particular shell this was the few uh things in short i said you given by neil por many other things was given but these are the few things all right given by neil bohr all right apart from accepting the neil gore's atomic model was that the kneel board for the first time uh told us about the stability of the atom minded for stability of the atom for the first time he told us stability means he was the first person to calculate the energy not it of an electron in an atom here's the first question he gave us the formula e n is equal to minus two pi square me four z square by n square h square accordingly we calculated the energy in the ground state just i was speaking to you so in this way completely we cannot discard his theory because from every concept we l we need to learn something and we need to move ahead neil bohr was the first person to give us the radius of an electron from the nucleus our n value we calculated radius of a particular shell neil bohr was the first person so to say to give us a velocity of an electron in a particular shell so a lot of things they did we cannot completely discard all these things but few things the conceptual part we can discard it and we can move forward so hence i use the word failure so don't think that neil bohr's atomic model why did i explain you so as to say you that that nilborg's atomic model was not completely discarded it was not completely discarded living behind a few things we accepted the nail board's atomic model the few things means again i repeat the conceptual part we discarded it and we moved forward got it clear because the better science says about the spectroscopic method says us that apart from the spectral series we have got the final spectral series also okay so let us move forward now ah that is the development of nilboat's atomic model what you find is that it uh took place from the plant's quantum theory isn't it if you remember it that is after the other force atomic model i gave you the electromagnetic wave theory then i gave you the plant's quantum theory the drawbacks of the electromagnetic wave theory came from the planck's quantum theory so the birth of the nilbort's atomic model took place from the plant's quantum theory similarly i am going to say you now about the de broglies dual nature of matter as well as hissenberg's uncertainty principle all right this took place or this gave rise to a new model that is called quantum model of an atom quantum or it gave rise to a new mechanics that is known as quantum mechanics we can say that all right it gave rise to a quantum mechanics we can say a new model it gave rise to a new concept it gave rise to we can say that clear fine so understand so hence here we cannot ignore the deep broglies concept of the hisenberg's uncertainty principle because this will give rise to a new concept a new model that is quantum mechanical model or the quantum mechanics but you can say it about it which you are going to study later on so hence we are starting from d broccolis what you can say concept what i said d broglie's concept of dual nature of matter the produce d broccoli all right b broccoli's concept of dual nature of milk so what d broccoli suggested us he said that every material object like this pen all right which is moving the pen is not moving of course uh the car which is moving on the road a ball when you're when a bowler bowls towards the batsman that also is moving all right a football is moving a bus is moving a train is moving and electron is moving what except all these the macroscopic particles as well as the sub atomic particles the microscopic particles electron protons and neutrons all right he said possess dual nature that is it is having both particle nature as well as wave nature listen carefully according to d broccoli all the material objects in this universe has got dual nature it is both particle nature as well as wave nature correct that is whether a car moving on the road whether train is moving on the track whether a ball is moving on the field whether an electron is moving on a shell correct so every particles or material particles whether it's macroscopic or microscopic whether it is microscopic or sub atomic particles they possess dual nature that is both particle nature as well as wave nature all right it poses now we have to prove it this particular thing of course we know it it was said by einstein also he said us that it is an electron is of dual nature that's particle nature as well as wave nature he said from black body radiation from photoelectric effect from electromagnetic wave theory we came to know about it all right it was said by einstein already now the new thing which he he added the d probably is going to add is the mathematical relationship with the new thing which is going to add it all right now according to deep broglie see we he said that that according to plant's quantum theory we know it that e is equal to h nu understood the concept what we want to say that everything every material object in this nature is of dual nature from there he started its both particle as well as wave nature so from the planck's quantum theory we know that e is equal to h nu we know it from the einstein's mass energy relationship we know v e is equal to m c square or rather i should say e is equal to delta m square now both are e we can equate it both are energy now we can equate it so h nu is equal to m c square now nu means what is that c by lambda we've read it c is equal to mu lambda so nu is equal to c by lambda we have studied so instead of mu i i can put it new means frequency c by lambda c is the wave velocity lambda is the wavelength got it m c square mass into here this is stand for what the velocity of light here m is the mass and c is what the velocity of light which is 3 into 10 to the power 8 meter per second all right find it mind it here also same thing see velocity of light so understand what i am doing so 1 c i can cancel it so i get it h by lambda is equal to m into c now mass into velocity what is mass into velocity momentum we have studied already momentum linear momentum so h by lambda is equal to p now h is a constant isn't it plant's constant so what i can say is that that instead of this i can write it that p is inversely proportional to lambda because h is a constant here x is a constant so i can say that is p is inversely proportional to lambda or lambda is inversely proportional to p whatever it all is so in this way this was said by deep broglie now we'll analyze it we'll understand it this particular further that means according to deep broadly that is every material particle which is moving has got a momentum definitely it has got mass it has got velocity mass in the velocity is nothing but is your momentum it has got momentum now what you find is that ah that is that momentum is inversely proportional to wavelength that was said with d probability it's proved obsolete it is inversely proportional to wavelength that means if a body has got larger wavelength it has got a very smaller momentum if a body has got a very smaller momentum it has got a very what you can say a smaller wavelength then it has got a very larger momentum now which body has got a larger or what you can say maximum momentum like a truck the mass of the track you see and the velocity which is moving you see you multiply it and see it is having a larger momentum all right mind it a mass of the track it's some around some 1000 kg or something like that it may be got it here or a bus or a car or a scooter or a cycle or a train whatever it is the mass is much much much much much larger than that of an electron we can say that clear so mass into velocity if you multiply then you will be getting the momentum value is huge large now if the momentum is more the wavelength will be less got it but for the subatomic particle the mass is quite negligible for an electron it is 9.1 into 10 to the power minus 31 kg into the velocity of the electron which is nearly to that of light we consider that clear which is nearly what it is same as that of light 300 to the power eight if you multiply it then the momentum is very small so wavelength is large that means what you can conclude that de broglie is dual nature of matter de broglies listen carefully deep broglies dual nature of matter is has nothing to do with our day-to-day life because it has nothing to do for macroscopic particle it has to do with microscopic particle now why did i say it has nothing to do in day to day life because in a day to day life are you dealing with electron protons and neutrons no you're not dealing with electrons protons and neutrons are you dealing i will say this is an electron this proton is a neutron are you reading a common man is dealing with electron protons and neutrons no even as even a chemist also is not dealing with electrons protons or neutrons it is dealing with atoms or molecules we can so that not also atoms molecules we can survive because atom does not exist independently how an electron will exist clear so hence deep broglie's dual nature of matter deep broglie's concept has nothing to do in a day-to-day life let me say you that all right it has something to do with what you can say subatomic particles now i will explain this to ah explain this so hence what you find is that you understood the fact that if a body is having larger momentum then the wavelength is very small very very small very small negligible and if your body has got a smaller momentum then the wavelength is very large so which body is having larger momentum the macroscopic particle which is having larger momentum so the wavelength is negligible and in case of sub-atomic particle the wave the momentum is smaller so the wavelength is larger large if it is larger means what i mean to say it is visible at least if it is not visible to the naked eyes it can be visible through a microscope but when a car is moving on a road are you seeing the car are you seeing the wave now you come to the point all right when a car is moving on the road when a bus is moving in the road when a bowler is bowling towards the batsman the batsman is seeing the ball or he's seeing the wave he's in the ball when a ball when a car is moving on the road you are losing the car are you seeing the wave no that's it what i'm saying why the wave is not visible because wavelength is so small you will see it i'll prove it now when the wavelength is so small it's not visible so that reason i said that the de broglies concept has nothing to do in our day-to-day life because if the wavelength is so small now how much it is let us calculate it then you will understand it much more better all right let us calculate it okay let us calculate this particular part so ah that is let us say lambda is equal to h by theta h by p so is equal to h by p is nothing but mass into velocity so h is 6.626 into 10 to the power minus 34 mass of let us say a ball empty a ball got it of mass 0.1 kg all right mass i am taking to bear 0.1 kg here listen carefully 0.1 kg i am writing it as mass i am taking to be as 0.1 kg all right and the velocity with the ball is moving is let us say let me take a 60 meter per second let us say 60 into so if you uh if you see 0.1 into 636 then this is six point six two six and this is six and nearly it gets cancelled okay for that is nice two because it will be easy for me to calculate zero point one into sixty six and this is six point six two six so nearly it gets cancelled nearly so what you find is that approximately you get it the value to be as 10 to the power minus 34 meter because we have taken 60 meter per second so approximately lambda you get it to be as let me make lambda otherwise you'll not understand lambda to be s 10 to the power minus 34 meter yes or no see calculated lambda is equal to h by ph by mp i put the value of mass and velocity which nearly comes to be six i have cancelled it and approximately approx the value is 10 to the power minus 34 meter now tell me when a ball is moving with a speed of 60 meter meter per second because of that clear will it be ball is visible or a wavelength is visible this wavelength will result in this wavelength will be visible to you by any powerful microscope also it is not visible it is not visible to the naked eyes forget about it all right but it is not visible to a by powerful microscope also hence i said that lee broglie's concept is based upon a sorry de broglie's concept which he gave us is true for or it is valid for sub atomic particles it has nothing to do with the particles which is there in our day-to-day life like thus what you can say the macroscopic particles i said for that particular reason all right clear it is true for sub atomic particles minded here instead of this uh 0.1 if i put the mass of the electron 9.1 to the power minus 31 kg and if i put therma the velocity of the electron which is 300 to the power 8 you will see the this particular value comes to be larger than this it will come to be around 10 to the power minus 5 or 10 to the power minus 4 meter of course it is visible by a powerful microscope what it now de broglie's concept what is de broglie's concept of dual nature of matter it is valid for sub atomic particles all right but apart from this deep broadly ah gave us some more clarification as i said earlier now we are going to see that particular one