9 ms·
Why do electron shells have set limits? (1999)
- saurik 6y agoI feel like this answer is "no, there is no reason for that to be the sequence you are seeing: it is an accident, as you can see from this careful analysis which demonstrates exactly why it is that sequence"... it is like saying "I noticed a bunch of random processes fall into a normal curve, is there a mathematical reason for that?" and saying "oh no, that is entirely on accident; here, let me show you the math for how a particular kind of random selection causes that exact distribution you are seeing, along with the equations that characterize if... as you can see, no math is involved here: this was just an accident" :/.
- deleted 6y ago[deleted]
- hinkley 6y agoIn this vein, I really enjoyed 1brown3blue breaking down why prime numbers form patterns when graphed in polar coordinates. https://youtu.be/EK32jo7i5LQ https://youtu.be/EK32jo7i5LQ
- chadcmulligan 6y agoThat is one of the most artistic expositions of mathematics I have ever seen.
- stallmanite 6y ago3blue1brown is most likely the greatest math teacher alive. I’ve looked far and wide and found nobody who competes. Any HN’ers have suggestions for other math educators working on his level?
- boublepop 6y agoI think the intention was to say only that it’s “an accident” that they are double quadratic numbers, not that they have the exact values they have. Which is intended to say that the reason is different even if the result is the same.
- Viliam1234 6y agoIs it "an accident" that 1 + 3 + 5 + ... + (2n-1) = n^2 ? I suppose the only way to get quadratic numbers "non-accidentally" would be to have the electrons stand in n×n square formation.
- xingyzt 6y agoThese are the numbers that ‘wrap’ around themselves to form squares. 7777 5557 3357 1357
- Crazyontap 6y agoForgive me for posting this idiotic question in advance since I have very little knowledge of physics, but I have often been confused about one thing recently. From what I could gather a little isn't the whole electrons revolve in orbits thing proved false and outdated like universe is made of ether? I heard that even the iconic atom logo is all wrong since it is proved that electrons don't revolve around anything rather come in and out of existence and present themselves in probability clouds. If that is true then why do we still keep talking about shells and energy levels? Like I said my question may sound like a troll but I assure you it's not. Just want to know what's what.
- acomar 6y agothe orbitals aren't neat rings but there are definitely orbitals. they're shaped weirdly as they represent the space two electrons will probabilistically occupy. you can't pinpoint an electron and say it is precisely here in the orbital but there are fairly high odds that it's in the orbital.
- deleted 6y ago[deleted]
- irjustin 6y agoThere are orbitals[0], but they're not so nicely circular like in that "atomic" atom that dominated from the 1950's. Each energy level has a different shape. Also, they don't 'orbit' like planets. It's now a probability space[1]. i.e. You will _likely_ find electrons in this 'orbital' somewhere, but could be anywhere.... but you have to go looking for them. Once you've found them, they're instantly somewhere else in a completely unknown area of that orbital. [0] https://en.wikipedia.org/wiki/Atomic_orbital https://en.wikipedia.org/wiki/Atomic_orbital [1] https://en.wikipedia.org/wiki/Atomic_orbital#Shapes_of_orbitals https://en.wikipedia.org/wiki/Atomic_orbital#Shapes_of_orbit...
- jiggawatts 6y ago> instantly somewhere else in a completely unknown area of that orbital. Mr Einstein may have a few words to say about that.
- avalys 6y agoThis is such a classic physicist’s answer. It starts off promising, with a lot of context and detailed exposition which leads one to hope that perhaps it will be pulled together into an enlightening explanation at the end. But when one reaches the end, one finds merely the truism “It is this way because that’s what you get when you solve the equations.” (yes, I have spent a lot of time working with physicists.)
- deleted 6y ago[deleted]
- deleted 6y ago[deleted]
- mhh__ 6y agoThat's because it's really hard to explain physics to non-physicists without using mathematics. The clever part isn't classifying the orbitals, it's finding the Schrodinger equation in the first place. We knew electrons had wavelike properties, but what equation did they obey? Even with hindsight it's still a difficult thing to derive - the relativistic answer is actually wrong, for example. You reach the truism because the equations take years to learn - in engineering you can just take the result and run but in physics you have to be careful to understand what you're doing. The Schrodinger equation for hydrogen isn't that difficult to solve (try it), but conveying that process in English is difficult.
- vertbhrtn 6y agoMy understanding of QM is very naive, but Schrodinger equation seems really simple to me. I could probably even explain it to a 5 year old. I'd show a few pictures of standing waves on a drum surface: the first two energy levels create simple shapes, higher levels create more sophisticated shapes. Then I'd say that an electron is such a wave. Then I'd introduce the idea of electric potential: I'd put a heavy thing in the center and say that this is how the atom's nucleus warps the electric field; and this changes the wave patterns somewhat, but the idea remains the same. Then I'd say that often multiple standing waves mix together and we get a quasipattern that oscillates between a few standing waves. That's really it.
- matthewfcarlson 6y agoNot sure what this says about me, but before I looked at the year I thought this was about electron apps as command shells
- kfarr 6y agoI was thinking like wow electron has been around a lot longer than I thought!
- mattigames 6y agoOr from a different timeline where its 1999 and you can create electron apps by bundling them with ActiveX and Internet Explorer 6 ~shivers~
- matthewfcarlson 6y agoYeah- it's not a pleasant thought. It's like some horrible episode of twilight zone made just for developers.
- dboreham 6y agoBecause those are the values specified in the simulator's .ini file? I suppose they probably upgraded to a .yml file recently..
- nullc 6y agoIt always seemed natural to me that the number of electrons would grow quadratically with the distance (principal atomic number), just like the surface area of a sphere grows quadratically with increasing radius. I feel like the author of the comment calling it "by accident" would be extremely unhappy with number theory. In number theory all sorts of properties seem to crop up "by accident" but turn out to have incredible consequences and you realize that virtually every "accident" couldn't have gone any other way without destroying all of mathematics.
- whatshisface 6y agoThe electron shells themselves are in reality 3D objects that go all the way to the center, so it is a little strange after all that it increases with the surface area.
- number6 6y agoIs this true? I mean its a model. Aren't electron shells the quantum states of the electron fields?
- thicknavyrain 6y agoIt is true. The classical wavefunction of a ground state electron overlaps pretty heavily with the nucleus of an atom IIRC.
- jeherr 6y agoOnly for s-orbitals. Anything with a quantum number l>0 has 0 probability at the nucleus.
- Causality1 6y agoIs it? I'm not a physicist but it seems like another natural infinitesimal, sort of like how a black hole's singularity is a point of infinite density whose infinity isn't a factor in calculating the total mass-energy of the black hole.
- tmsh 6y agoThere's a series I've enjoyed recently: https://www.youtube.com/watch?v=zKbZeUvPnWI&list=PLpH1IDQEoE8Q8842yVe-V8m7PN-R9rlwi https://www.youtube.com/watch?v=zKbZeUvPnWI&list=PLpH1IDQEoE... "How Small is it" by David Butler. Offers a nice summary of electrons and goes deeper into the Higgs field. My two cents - after watching it - is it could all (i.e., wave/particle duality of electrons) be explained a lot more clearly if we just accept there is another dimension in space that electrons move into and out of, which we've not yet figured out how to observe. Would explain dark matter / dark energy a lot too. The model seems so incredibly simple to me that I just don't get why more people haven't tried to build on it (am so busy with other stuff I doubt I'll have the time to figure out unexplained Cosmological or other phenomena that could be better explained by this model). But it seems really straightforward this way. Electrons are small enough, independent enough to move out of and back into another magnitude of space that we can't measure. To us in 3-space it looks like they leave and come back (the idea of a particle being a "wave with itself" is less clear if you ask me). Everything is particles, it's just some particles have axis of motion in space that we don't know how to perceive yet. One can think about it by analogy. Suppose we all lived in 2 space. If particles in 2 space where small enough to detach from our plane and pop up and down above and below the plane they would seem to appear and disappear. It's the same thing with 3 -> 4 space. At some point people will realize that thinking about space as 3 space only is like thinking that the world is the center of the solar system. Our three dimensions are simply the closest / most defined / perceived ones to us. They're not even the "central" ones. They're the closest one's to our perception / how we've evolved. If you get into the smaller spaces of things, there's less binding energy that constrains matter and more flexibility in moving between other dimensions. Likely there's a major 4th dimension that matter moves through / oscillates if you prefer since it's smaller particles that move the most (though cosmologically we see the effects in the large). And likely once you get deep in the 4th, there's a fifth, etc. Again the analogy from "Flatland" / 2d space is you don't realize the freedom to move into 3 space until you separate yourself from the structure of what Flatland is made of at the sort of macro level. For us in 3 space the macro level is atoms. As you dive deeper inside, you're not bound by these constraints. Gravity, everything can be modeled as particle forces if you just realize there's dimensions we don't perceive at the macro level yet (but which can be perceived indirectly by their effects on our 3 space - just as in time you can figure out what something moving in and out of a plane is sort of doing in 3 space).
- deleted 6y ago[deleted]