Atomic structure part 5

Added: 2026-05-12

[00:00:00]after the discovery of electron we will see the dystoria proton now proton was discovered by goldstein electron was discovered by thomson proton was discovered by goldstein goldstein discovered protons now how now see goldstein was very clever he was a very clever scientist now goldstein was knowing this particular fact that atom is neutral in nature electrically neutral in nature even we also know it that atom is electrically neutral in nature now elect electro what you can say electronegative particles was already being discovered all right that is the particles having negatively charged has already been discovered by thompson so definitely goldstein was knowing about it that if an atom is electrically neutral negatively charged particle is already discovered then definitely there must be some positively charged particles present in it due to which atom is electrically neutral and not only was knowing this he was also knowing that there must be equal number of positively charged particles why because minus 2 is there how much you require to make it 0 plus 2 minus 2 plus 2 is 0. if minus 3 is there how much is required to make it 0 because 0 means neutral it is how much it required plus 3. so this idea was known the gold stream for that is an idea goldstein was very clever scientist so he was knowing the fact that negative particles is already discovered so definitely an atom consists of positively charged particles present in it and that to equal number of positive charged particles is being presented so this idea was known to goldstein before he started doing the experiment this idea was there in his mind for that purpose i said now same thing you can see this he took a discharge tube all right same thing a catheter but the only difference is that he took a perforated cathedral perforated now perforated means what so you can see i have taken a plate all right let us let us think of this is a plate is there and holes are present in it perforated means holes are present holes are present all right that is perforated so you can see the lines need nothing but represent the holes the holes are being present in it okay so it took a perforated cathode that's it now and this is same thing is connected to a vacuum pump got it i'll be taking a gas in it which is at low pressure the gas is at low pressure something very very low pressure 0.001 millimeter of mercury the gas will be present in it same setup the only difference is that we have taken a perforated catheter that's it now what you will find out what goldstein observed when the pressure now listen carefully when the pressure was very very low because at high pressure it is not going to ah what you can say flow because ah in high pressure already i have said you many times that the molecules will be present and the molecules are the poor conductor of electricity the molecules of air or molecules of gas they do not conduct yesterday remember this particular thing molecules and atoms are neutral in nature and then it will never conduct literacy unless and until you won't get the charged particles it is not going to conduct your city okay so that you should keep in your mind always so hence it is not going to conduct when the pressure is higher when the pressure is very very low then what will happen is that when you pass the electric discharge through it the gas will get ionized and when the gases will get ionized at that time goldstein what you saw he saw that this end he saw scintillations scintillations means same thing fluorescence this end he saw ventilations means this end was glowing previously the other end was glowing in the previous experiment thompson's experiment in goldstein experiment this end was glowing so when this end was glowing the glowing of this particular end what does it prove that the rays is passing through this particular perforated cathode and the direction of the rays was from positive to negative all right so hence this particular race was called as nothing but positively charged race all right and it was also called as canal race it is known as canal race why it is called as canal rivers because it passed through the holes like in uh you can see it cannot you have seen a canal the canal the water is being passing through it so here's the same thing through this holes the uh ions are passing through it the rays are passing through it and as a result we got scintillations here due to this particular reason all right now we did not get a scintillations completely here we got the scintillations where are the holes are there their holes are here we got scintillations here the holes are here we got scintillations here the holes are here we got scintillations here but it's in this way wherever the synth the holes are there we got scintillation so the fluorescence there all right so as these rays pass through the holes so hence it was called as canal race all right so it was directed from the anode towards to that of the cathode so it is positively charged how do we continue its positively charged very simple you take ah that is negatively charged plate here and you take a partially charged plate here you will see the rays instead of passing straight it will bend towards here towards the negatively charged plate how do we come to know here you coat with fluorescent substance all right here you coat with fluorescent substance zinc sulfide you coat it you will see this part it glows the glowing of this part proves that the rays are positively charged because it bends towards the negatively charged plate are you able to understand the rays are positively charged how do we come to know because the rays bends towards a negatively charged plate you can see that the rays is bending towards the negatively charged plate it's not bending toward positive it bends towards the negatively charged plates by that it's been proved that rays are positively charged okay in this way we got that is the discovery of the uh that is protons was being done now white was named as protons that also let me tell you protons has come from the word proteus and proteus means first in latin language it means first you have heard it also in cricket that is south africans they are called as a proteus because it is believed that south africans are the first people on this earth surface it is believed i don't know whether they are first or second or third it is believed historians believe that they are the first people on the earth surface so hence they are said to be as proteus all right so in cricket you heard it this particular term proteus all right so hence it has come from the word proton has come from the word proteus proteus means first it is mean to means to say so hence you can see the protons is being discovered in this particular manner now if you see the characteristics of the this particular race or the protons you will find it out that it has got the similar characteristics as that of that is cathode rays similar characteristics got it now here i am not using the term and address mind it i'm not using the term all right there i use the term cathode rays i'm not using the term anode rays because anion rays are not produced from anode and rays are not produced from allot then how it is produced see it is being produced from the residual gas residual gas means see when the gases is ionized when hydrant loses an electron what do you get we get positively charged particles these positively charged particles travels from added towards that of the cathode and hence we got the scintillations got it now it is not produced on planet so hence we cannot call it as anode rays this one okay mind it it is not called iron rays because it is not produced from anode it is produced from the residual gas the gas which is being left out in this particular uh this cathode ray tube which got ionized and hence we got this particles the possible charge particles which travels from the anode towards that of the cathode as a direction was from another to cathode in that case you can say it is analogous as a direction as the direction is from annette to cathode on the basis of that you can say it is an address but you can't say it has an address why because it is not produced from another find it it is not produced from added all right understood this particular point remember it actually now if you see the velocity of the cathode rays and the anode rays then cathode rays travels faster than that of the anode risk why because cathode rays consist of negatively charged particles and which has got a negligible mass while if you say it has another rays suppose for the time being let me consider it as anode rays all right then this consists of protons positively charged particles and its mass is quite heavier that of an electron the mass of an ill proton is 1.672 into 10 to the power minus 24 gram how do we find it out same method that is e divided by e by m here the value of e by m is different all right the charge is the same charge is the same because what i said in the beginning itself that he was knowing who was knowing goldstein was knowing that an atom is electrically neutral because it contains same number of positively charged particles so what is the charge of an electron minus one point six zero two into ten to the power minus nineteen kilo minus what is minus because charge is negative so what is the charge of proton same it is the only difference is that it will be plus one point six zero two into ten to the power minus nineteen coulomb definitely the proton is positive so it is positively charged electron is negative it is negatively charged electron and proton you added you will be getting neutral it will become zero all right so hence you can find it out that the charge is the same the value of e is the same the only difference is that in case of electron it's negative in case of proton it is positive and the mass of a proton is 1.672 into the power minus 24 gram which is estimated that the mass of an electron is listen carefully the mass of an electron is one by one eight sorry three seven times that of a proton one by one eight three seven times that of a proton all right the mass of proton is this one point six seven two into the power minus twenty four so one by one and three seven into this value if you do then you will get the mass of the electron which is nine 9.11 into 10 to the power minus 28 gram so an electron is quite negligible compared to that the mass of the electron is quite negligible compared to that of a proton for that purpose the velocity of the cathode rays is much more than that of the anita trees if you consider correct otherwise the properties is the same all right it consists of possibly charged particles it also ionizes the gases to which they pass it also causes fluorescence as you can see it causes intelligence it also what you can say falls on the metal plate to cause heating effect on it if you place up this mica film it also rotates because there is an inter conversion of energy same thing it is whatever the properties of the catheter is you got it the similar you will get it for the anode rays of prefetal you say got it otherwise you i told you that we cannot use the term the anatomies generally we use the term canal race all right so in this way protons was discovered by goldstein and this is the mass of the proton and how we find it out i said it thank you