Learn about Advanced Placement Chemistry, Atomic Theory 1, in this comprehensive video by bannanaiscool.
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Male Speaker: Okay, it's the end of the 1800s and the physicists scientists think that they got it all figured up. Here is what they think. Well, we got matter and we got waves, they are totally distinct from one another you know, matter particles they have mass and they have location they are localized and those waves they are totally delocalized, they got no location what and where that you can describe and look at them they are just weightless, they are masses. Then along comes Max Plank into the 1900s and here is what he says, through all my research and all the things that I have been looking at, matter is it absorbs energy or releases energy as weight, it doesn't do so in a continuos fashion which is what you would expect but matter absorbs or releases energy in specific amounts in chunks in quanta. Now what does that infer, that may be that the energy itself is quantized or packaged in chunks or this threw everybody upside down and here is what we develop from that, lets go back a little bit, look at some of the physics, we have to understand the physics before we get to the chemistry later and talk about where electrons are in the atom itself. Okay, the speed of light equals wavelength times frequency, I am abbreviating frequency f here because that's kind of standard and also sometimes I see it written v for frequency, alright and of course the wavelength is just in a wave it's the length between two equivalent points in that wave, here peaks or could be that the troughs, now that's the wavelength and the frequency how many of these pass by in one second, that's going to be the frequency, hence the unit for wavelength is the meters and this is per second, so you get the speed of light 2.9979 times 10 to the 8 meters is how far it travels in one second, its very very quick isn't it? If you travel from earth to the moon, 1.2 seconds are you ready, go stop, ah there you are on the moon that's how fast the light travels, impressive hey. Max Planck said okay quanta, chunks so the energy that EMR electro magnetic radiation like the light, heat, microwaves, television waves, radio waves they all travel at the speed of the light. The energy of that equals constant 6.626 times 10 to the negative 34 joule seconds times frequency. If you know the frequency of EMR, you can calculate the amount of energy that it possess oh that's pretty cool okay because Planks constant takes it to account that you can you understand that the energy is in or the EMR is in quanta or chunks. Einstein goes even better he says you know what I can do some formulas here and I will actually suggest that E equals mc square or not only do we have chunks okay but there is an intra convert ability between mass and energy, oh man if you know the mass of something accelerate to the speed of light square you can calculate the amount of energy that it possesses okay, oh oh oh boy, this was absolutely validated of course when nuclear chemistry started in the 1930s. So, we know that we can take a certain mass of something like your radium and we can annihilate it and convert the matter to energy and we can calculate how much energy come to half of that nuclear reaction which is actually nuclear fission. Look at this, you can substitute into this formula hf for E and of course lambda frequency for C, you know that means and found this out that if you have the mass of something you can actually calculate because you know all these are the constants, you can calculate it wavelengths of a particular piece of mass or is very -- the Bohr takes this and he does himself somethings that are quite fascinating with trying to determine the position of the electron and the atom in terms of energy levels by using a demonstration like the one we are going to see right now.