Atomic Structure Bohr's Atomic model 2

Hinzugefügt: 2026-05-12

[00:00:00]now just i have seen you that the energy of a particular shell is quantized means it has got a fixed value quantize means fixed value not any value of its own see theoretically if you see then you may say to me from the nucleus we can have infinite number of shells correct theoretically it is possible then we can have infinite number of shells but electrons is not found in all the shells electrons are found in that particular shells listen carefully electron is found in that particular cell whose energy is fixed which has got a definite value of energy not any value of its own not any value of its own and its error and its what you can say value is quantize quantix means fixed value whole number just now you saw it what i gave it to you all right just now minus one three one two kilojoules per mole i said you the first shell then second cell also we can we can calculate by putting the value of ns2 in the formula we can calculate it all right in this way we can say that the energy of a particular shell is always that is fixed but we can't see the cell it is this cell it's it is imaginary i told you earlier also this is imaginary for just making for me to to make you understand we are saying this particular thing it is imaginary completely the shell it actually does not exist neil bohr if they it said that just to explain theoretically an atom that electron where it is they present in an atom audit where the nucleus and what the the neutrons and protons consist of so this particular shells now nucleus is there of course the neutron electrons which are moving in a particular cell that is imaginary we can say that so hence i said you discrete uh what you can say value of energy for that is message and its angular momentum is also quantized now what is momentum you read in physics this one momentum means the product of momentum is p product of mass into velocity this is linear momentum now when i say angular momentum it is m into v into r r means radius of a cell because the cell is not linear it's not straight it's not straight shell is circular you can see so circular means it will it will have a radius this is a radius from the nucleus will have a radius you have to put the value of the radius then you'll be getting the angular momentum so the angular momentum is also context whose value was given by neil boras and h by two pi but from where this value was come nilbor could not say he could not say later on it was said by another scientist you did it later on it was said by another scientist from where he got this particular value this was just assumed by neighbor see previously the scientists they used to assume something and their assumption was so powerful it was so correct that later on when this value was calculated by some other scientists they found it was more or less correct in this way when you study science you will see that you say that assumption yes they were such powerful all right they used to think their logic was so powerful so great because they did not used to mark it up understood they used to think and they used to say all these things it is not that whatever it came to his mind like yesterday in the night he dreamt something and from the dream somebody came and said see the value is nh by 2 pi you write it down it's not in that way they when they told something that was having some logic even if they could not prove at that particular time why they could not prove the reason is that whatever the resources was available at that time it was not sufficient for them to prove for that reason they could not prove it but later on when the other scientists approved they found that it has been correct so nilbor could not prove it but he assumed a particular value value of the angular momentum he assumed mvr is equal to an h by 2 pi and its value is also fixed it is quantized it is not any value of its own it cannot be any value theoretically it can have any value but as i said you practically you cannot have any number of shells you can have a definite number of shells a fixed value that is a whole number all right you cannot have any particular number remember all these things so next is that as i said you electrons is moving in its shell neil gore suggested that let me just wind up the nilbort's atomic model he said that we are having a nucleus and electrons is moving in a particular shell whose value value means energy is fixed or quantized it cannot have any value of its own its value is different and the first shell this one has the what you can say having the lower energy level and the electrons which are present in the first shell they are said to be in the ground state after that when you move from the nucleus the energy increases increases energy gradually it increases does not decrease it increase all right fine now next is the outermost shell is considered to be as the valence shell we can say it is a balanced shell outer moisture and the electrons which are present in the outer muscle are considered to be as a valence electrons and they determine the chemical properties of an atom because shearing the transfer of electron takes place that is a loss or gain of electrons all takes place from the outermost shell only not the inner motion because the innermost shell the electrons are the bound electrons and the outermost shell the electrons which are present they are considered to be as their free electrons say they determine the properties of an atom of an element we can say that okay i hope you understood the nilbort's atomic model now as i said you that kneel board such as suggested that that we are having shells around an atom around the nucleus got it and i said you also k l m n in this way so he gave us the electronic configuration electronic configuration is what it is nothing but the distribution of electrons in different shells in an atom all right distribution of electrons in different shells of an atom is called the electronic configuration of the atom the distribution of electrons that in a particular shell how many electrons is there it cannot be any number because as i said you electrons remains nilbor suggested that the electrons in a given shell it continues to remain in that particular shell unless and until some external energy is provided to it so it will infinitely remain in that particular shell unless and until you provide some energy to it all right so hence a particular shell has got a definite number of electrons also it has got definite energy and the electrons which are present in a given shell has got that much amount of energy suppose if an electron is present in the first cell so the electrons which are present in the first shell they will have the energy of the first shell electrons which are present in the second shell they will have energy of the second shell electrons which is present third cell they will have the energy of the third shell in this way it goes on okay now how many electrons are there in a particular shell now this particular ah what you can say it was given by the concept was given by bohr and bury the two scientists it is known as bohr bury scheme they gave us a scheme according to that particular scheme the number of electrons in a given shell the maximum number of electron number of electron maximum number of electrons in a given shell is given by the formula 2 n square where n is equal to number of shells what i said the maximum number of electrons in a given shell is given by the formula 2 n square that means if i use this formula the k shell the k shell will have two electrons k means n is equal to 1 isn't it now l shell will have how many electrons you put the value of ns2 l means what n is equal to 2 all right so what do you get 8 electrons in this way m n is equal to 3 you put it you'll be getting s 18 electrons in this way you'll get 32 electrons in this way i am putting minus charge because electron is negatively charged or that is an important you know that in this way the first shell consists of 2 then 8 and 18. so we came to know that this is suppose a nucleus and the first shell which contains how many electrons 2 the second shell contains how many electron maximum this is maximum minimum it can be anything it can be one also like first shell the minimum can be one but max it cannot be three maximum is two understood so here the maximum is eight 8 in this way see this arrangement this arrangement which i am doing it it is known as the electronic configuration of an atom this is the arrangement of electrons in a of in in particular shell is called as an electronic configuration this is known as the electronic configuration that the first shell two maximum second cell eight maximum third shell 18 then fourth shell 32 in this way this is the first point all right given now second point is very important if a particular shell is the outermost shell any shell it can be third cell for itself it's an initial is outer motion the maximum number of electrons in the outermost shell is eight only it cannot be more than eight it cannot be more than it whichever is outer moisture the maximum number of electrons will be eight only all right clear up this particular thing now next is uh when you write electronic configuration you'll come to that and teach you know the electronic configuration the next thing is that when you are filling after a particular shell the first shell is filled let us say two electron second cell you split eight electron third silicon 18 electrons all right now remember it remember here that when you are filling a particular shell you must remember it that it's not that you are filling a shell and it is going on the electrons is being added you have to remember here that the outermost shell should not exceed eight electrons the outer moisture should not exceed even if the third cell the capacity is 18 but the outer muscle if the third cell is outer most shell then it cannot have more than eight electrons all right so you're not supposed to fill according to lee like suppose the third shell sir you said 18 so hence first you'll fill up the third shell then we will see that anything is left then we'll go to the fourth shell no as the uh what you can say the third still becomes outer motion eight electrons is filled automatically the fourth cell will be created because the remaining electron will go to the fourth shell in that particular way it is being done all right for example let me give an electronic configuration like potassium atomic number is 19.

[00:10:07]before production let me tell you how to write the electronic configuration of different element let us say oxygen 8 so it will be 2 6.

[00:10:14]how to six because first cell is 2 then remaining is how much 6 the second shelf is 6 max center of it is 8 now the 6 it is now next sodium 11 first is 2 second cell is 8 maximum so 8 plus 2 is 10 one more is remaining total is eleven so two eight and third cell will be how much one in this way all right suppose uh that is alpha sixteen so first here is two maximum second set is eight all right so eight plus two ten so remaining is 6 in this way it has been done in this way all right now let us come to 19 potassium as i have seen so first year is 2 second series 8 third cell is 9 30 9 so 2 8 to ten ten plus nine but can it be nine no because what i tell you if the third cell or initial is outer motion the maximum number of electron is what eight so it is two eight eight then automatically the fourth field is created that is one that is what i was saying it's not that the first the third shell will be filled up then the fourth will be no if the third cell is the outermost shell then it will have eight then automatically a four chill is created that is for one electron goes to the fourth shell in this way that you have to remember it the second part which is very important so let us say that is calcium atomic number 20 so 2 8 10 then it should be 10 10 is left so should we write 10 no 2 8 8 then 2 because if you write 10 it's not possible why it's not possible because 10 is the outer the third still is outer motion and outermost child cannot have more than 8 it cannot have so hence this will be eight the remaining is what two eight ten ten plus eight eighteen seven is two so two is outer motion two is the valence shell so number of valence electron in here it is two here the number of valence electron is one here the number of valence electron is one here the number of valence electron is six here the number of valence electron is six just like i said if an element have one two or three valence electrons then it will have a tendency to lose it is a metal now white will have a tendency to lose white will have a tendency to lose because always an atom tries to attain stability all right always an atom now listen carefully always an atom tries to attain stability becomes stable when the outer moisture is fully filled when the outer moisture is fully filled that is it has got either octet or duplet configuration duplet means if the outer moisture has got two electron that is that we duplicate and if the outer muscle has got eight electron that is a tvs octet so if the outer motion has got either update or duplicate configuration then it said to be what you can say fully filled now you might say me that's a now you're saying that is outer motion should be obtained right from duplicate means see there are two elements are there which has got only one shell what is that two elements hydrogen and helium so hydrogen atomic number is one so it is one shell helium atomic number is two so it is two all right that is two it is it's having only one shell so the element or the atom which has got one shell from where octet will come there from where octet will come octet will come from the signature the rule of octet comes from the second shell so if an atom has got one shell then it will follow definitely a duplet configuration because it has got one shell and the first one is fully filled done understood now so hence for that particular purpose here what is what i say listen carefully here sodium is having one electron the outer moisture to attain stable configuration it will lose one electron then outer muscle becomes stable eight here an atom has got six electrons in the outer muscle so will it lose six electrons or will it gain two electrons to attain stability definitely it is going to gain two electrons because that's easier what i said you will it lose six electron because if it is losing six it becomes duplicate if it is gaining two if six plus two if it is gaining two then the outermost shell becomes eight octet so which is easier to gain two or to lose six to gain two definitely lower number so hence for that particular purpose it gains two electron gains so gains which element gains electrons non-metals oxygen is a non-metal it's a gas sulphur is a non-metal it's a uh also on heating it changes into gaseous state so what you find is that so element which have got one two or three electrons in outer moisture like here you can see two electrons is there if it is losing two then the outer muscle becomes octage fully filled it becomes stable all right to attain stability because everything in this world wants to attain the stable configuration even you also wants to attain stability suppose if i ask you stand in one leg you'll not be able to stand for a long time why because it will be unstable the center of gravity will fall outside your body your radiant physics this thing so hence to attain stability you need to stand in two legs that's it and if you still want stability then you need to sit in a chair a short on a height chair according to your height you need to sit on a chair then you will become fully stable you can see that clear that's it so here also same thing and this element it is unstable in nature it will lose to electrons and will become stable because the outer moisture is fully filled it becomes see eight electrons outer mercury that attains the octet configuration becomes stable are you following so hence it has got a tendency to lose two electrons so calcium is what metal potassium is what metal because it is gain losing one electron here also you lose one electron and it becomes stable the outer moisture becomes fully fit so in this way the elements which have got a tendency to lose electrons so which element will have tendency to lose electron one two three they will have a tendency to lose because by losing electrons it attains the octet structure you can see it here you can see it here you can see it here and here it has got a tendency to gain by gaining electrons one more example i'll give you nitrogen let us say seven two five it has got a tendency to gain like chlorine seventeen two eight seven it has got two eight seven it has got a tendency to gain by gaining one electrons it becomes stable by gaining three electrons it becomes triggered so if an element has got five six and seven electrons in the outermost shell it has got a tendency to gain so it is a non-metal and if it is having like carbon six two four so two four means four it can lose four it can gain so it is a normal and neon let us say it is ten atomic number so two eight so it means it is fully filled all right argon it is eighteen so it is two eight eight again outer moisture is fully filled so it is stable here it is stable it is consisting of inert gas noble gas it has got zero reactivity why why it is not going to react because your autonomous shell is fully filled is going to react here the outermost shell is not filled here the outer moisture is not filled yet it is not filled it is not here it is excess fed so here it is going to lose here it is going to gain but here what it will do no lose no gain nothing since it is not here also same thing in inert so they are inert in nature they said to be us all right in this way we can say the electronic configuration thank you very much