Learn about Advanced Placement Chemistry, Atomic Theory 3, in this comprehensive video by bannanaiscool.
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Rob Lederer: So poor board. The formula doesn't work. Where are the electrons and what are they doing in the atom? Well, that's a big question. So Heisenberg comes along, he says, well I don't know and everybody goes, Oh that's really cool. Now, Heisenberg actually comes up with an idea that says, it's not that we don't know, we can't know. Because there is a certain amount of limitation that's available here, in terms of being able to find out where the electron is. Now look -- have an electron microscope, they are very powerful microscopes that can actually zoom in and try to find an electron in an atom. Well, you have to input a lot of energy into that and probably have to shine a lot of light on that little sample that you've got. Immediately by doing that, you are adding enough EMR to blow the electron from N equals one to N equals I don't know. And so, you try to measure it and we are limited now in terms of our being able to measure it properly, because it'll just blow the electron away. So, that the closer we come to knowing where it is, the less reaction. We know about how fast it's going or taking off to, and then the more we know about its speed, the less we know about where it is. Oh, there is Heisenberg's uncertainty principle. In formula, it's the uncertainty in the position of an object, time and it's the uncertainty in its momentum, which mass time speed has to be greater than or equal to Planck's constant over 4 pi. Okay, okay, here is what it means. You know, you wouldn't actually set off the thermal nuclear device to try to find out where the basketball is in the dark basement. Would you? No, no, no. Okay. So, you see then you wouldn't try to add massive quantities of energy to an electron to find out where it is, because you'll blow it away. Let's say however that we have a car whipping through a dark -- or something like that. So, if that's the case and we want to measure how, let's say, how fast it was going. If we can measure its position very accurately, which is what we can because measuring wise, and we can measure things to ten to negative 12 meters on this planet. That's how good we can measure stuff. So, we can measure that very accurately. And let's say that we know the car's mass. Well, if we take those numbers divided into this side, we can calculate not its speed, but the uncertainty we have in the speed of the car. And actually that number would be very, very, very low ten to negative 30 or something. Here is what it means. A very small number from this equation means a very small degree of uncertainty, which means that you are really certain. So, you could really know the speed of the car. Oh yeah, but now if you take, try to find out say, what the speed of an electron and let's say you could really measure that electron very, very well about ten to the negative 12 in terms of our ability to measure on this planet. And, you know, the mass an electron, which is in the ten to the negative 31 kilograms. And you divide that into this side, you get a number for its speed and uncertainty value for its speed that is so large, it approaches the speed of light. Here is what that means. If the uncertainty is huge, that means we are really, really uncertain about its speed. So, if you try to calculate the speed, we are totally uncertain about it, to a degree of, here is the speed plus or minus the speed of light. You have no idea how fast it's going. So, Heisenberg's uncertainly principle really sets the groundwork for the limitation that is involved in trying to find the position or the speed of an electron. So, where is it? I'm not really sure. What's it doing? No. Is it in the atom? Yeah. Yeah. Well, we are going to try to define where it is in terms of space of probability called orbital. But first, we are going to trying to give it an address.