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Why does the electron orbit the nucleus?

The lowest electron state in an atom has zero orbital angular momentum. So, the probability distribution function actually peaks at the position of the nucleus. If I recall correctly this results in a slight shift in the energy level.

There’s just no good classical analogy for what’s happening to quantum particles.
 
We can use equations to model the behavior of a ripple in an electron field.

We can model behavior.

This allows us to predict behavior at a certain scale.

There is a little question about Muon g-2 behavior.

Why does an electron have it's properties and thus it's behavior?

What gave it these properties?

That is a bigger question.
 
Why don't the electrons and the protons click together like all all things with opposite charges do?

The electron can only exist in quantized energy states within the potential well generated by the. nucleus. No zero energy state is allowed.

In classical EM, an orbiting electron would emit radiation and it would spiral into the nucleus. That was one clue that modern physics needed to be invented to explain the structure of the atom.

But it does happen! In neutron stars. If gravity is strong enough, the electron and the proton get smashed together. Of course they then turn into a neutron.
 
Why don't the electrons and the protons click together like all all things with opposite charges do?

The electron can only exist in quantized energy states within the potential well generated by the. nucleus. No zero energy state is allowed.

In classical EM, an orbiting electron would emit radiation and it would spiral into the nucleus. That was one clue that modern physics needed to be invented to explain the structure of the atom.

But it does happen! In neutron stars. If gravity is strong enough, the electron and the proton get smashed together. Of course they then turn into a neutron.
Sure, but the question was about atoms, not neutron stars.
 
There is no intuitive picture. And THAT's the point.
I.e., classical approximations are wrong. Does that make them useless? It seems to me that's in the eye of the beholder. One could ask the same question about planets: why don't they fall onto the sun the same way everything that goes up comes down? One could give the same answer: they have angular momentum so the planet would have to speed up to a ridiculous extent. One could raise the same objection to the answer: the angular momentum is carried away as gravity waves. It seems to me that doesn't make the Newtonian picture of celestial mechanics useless; YMMV.

Suppose light weren't quantized and the "ultraviolet catastrophe" were real -- how fast would an electron be going when it hit the nucleus?
Does not matter, classical EM radiation still carry angular momentum.
Sure; but how much angular momentum would leak away in the emitted light and how much would remain in the electron, hence, how fast would the electron be going? Back of the envelope, I make it about three times the speed of light...

Also, ultraviolet catastrophe is a separate problem.
Oh, okay, my bad. Can you explain the distinction?
 
But it does happen! In neutron stars. If gravity is strong enough, the electron and the proton get smashed together. Of course they then turn into a neutron.
Sure, but the question was about atoms, not neutron stars.
And in quantum mechanics, everything is more complicated than any simple summary. Once in a while, if the various energy levels are just right, the electrons and the protons in atoms really do click together like all things with opposite charges do. Radioactive rubidium-83 decays by electron capture. An electron and a proton turn into a neutron and emit a neutrino to carry away the extra angular momentum, just as if it were in a neutron star.
 
I.e., classical approximations are wrong. Does that make them useless?
That makes them less than useless.
It seems to me that's in the eye of the beholder. One could ask the same question about planets: why don't they fall onto the sun the same way everything that goes up comes down? One could give the same answer: they have angular momentum so the planet would have to speed up to a ridiculous extent. One could raise the same objection to the answer: the angular momentum is carried away as gravity waves. It seems to me that doesn't make the Newtonian picture of celestial mechanics useless; YMMV.
Your theory is not even wrong. Electron rotating around nucleus DOES lose angular momentum and DOES fall, in both in QM and in classical mechanics. It's just in QM it stops falling down when it reaches lowest possible orbit, which has zero angular momentum,
Does not matter, classical EM radiation still carry angular momentum.
Sure; but how much angular momentum would leak away in the emitted light and how much would remain in the electron, hence, how fast would the electron be going? Back of the envelope, I make it about three times the speed of light...
1/137 of speed C.
Also, ultraviolet catastrophe is a separate problem.
Oh, okay, my bad. Can you explain the distinction?
One is about black body radiation, another about electron falling on a nucleus due to radiation.
 
Electrons and photons really aren't like anything in human experience at the macroscopic scale.
Curious, why call out photons and electrons? The effects we see in atoms can be similar as well. The double slit experiment can be done with buckyballs which are enormously massive compared to electrons.

I do wonder whether it might be better to start by saying that it's futile to attempt any analogy, and just give students the facts, and show them the experimental approaches that allowed us to determine what those facts are.
Honestly, analogies are overleveraged for value. I hate analogies because they rarely ever describe what needs to be described.

What is an electron? It is mass bearing and negatively charged.
Is it a wave or a particle? It really seems to be whatever it needs to be at the moment.
 
What is an electron? It is mass bearing and negatively charged.
Is it a wave or a particle? It really seems to be whatever it needs to be at the moment.

To do organic chemistry you don't even have to talk about mass.

You abstract an electron to (-1) and call that it's charge and you can predict what it will do and where it will go.
 
That makes them less than useless.
If you say so. Forty-odd years ago I attended a lecture by Dr. Chandrasekhar. He opened with a demonstration of the power of dimensional analysis, using a classical model of the atom to derive a formula in a couple of minutes with which he calculated that the total number of chemical elements was about a hundred. Uselessness appears to be a matter of opinion.

It's just in QM it stops falling down when it reaches lowest possible orbit, which has zero angular momentum,
Only in the s orbitals. Most of the electrons in most of the elements still have orbital angular momentum.

...how much angular momentum would leak away in the emitted light and how much would remain in the electron, hence, how fast would the electron be going? Back of the envelope, I make it about three times the speed of light...
1/137 of speed C.
That's the speed in an orbit at the scale of an atom; we were talking what the speed would be if an electron were able to spiral down to the nucleus, about a hundred thousand times closer.
 
Electrons and photons really aren't like anything in human experience at the macroscopic scale.
Curious, why call out photons and electrons?
Because electrons are the things being discussed? I wasn't 'calling them out', I was just using them as examples. The photon I picked because it's a convenient zero rest-mass entity with strong relevance to electron behaviour, and exemplifies the fact that I am not just discussing massive particles.
The effects we see in atoms can be similar as well. The double slit experiment can be done with buckyballs which are enormously massive compared to electrons.
Sure.
I do wonder whether it might be better to start by saying that it's futile to attempt any analogy, and just give students the facts, and show them the experimental approaches that allowed us to determine what those facts are.
Honestly, analogies are overleveraged for value. I hate analogies because they rarely ever describe what needs to be described.
I rather like analogies, and I think they can be very helpful. But not in this case, because there really isn't a commonly experienced entity that is analogous to the things being discussed.
What is an electron? It is mass bearing and negatively charged.
Is it a wave or a particle? It really seems to be whatever it needs to be at the moment.
It really seems to be neither. It lacks features of both that are widely expected to be defining. For example, a particle has a defined location, and a wave occurs in a medium. Electrons (and photons, and other quantum scale objects) don't fit either criterion.

As soon as you say "an electron is like a billiard ball", students get a mental model of the thing that is going to need to be un-learned (probably with great difficulty) at some future date, if they want to pursue the subject.
 
Because electrons are the things being discussed? I wasn't 'calling them out', I was just using them as examples. The photon I picked because it's a convenient zero rest-mass entity with strong relevance to electron behaviour, and exemplifies the fact that I am not just discussing massive particles.
I think it gets lost that electrons aren't remotely special in this behavior. You are correct though that the subject was electrons, not just 'crap that does "odd" stuff in the quantum world'.

I rather like analogies, and I think they can be very helpful. But not in this case, because there really isn't a commonly experienced entity that is analogous to the things being discussed.
The problem is, people are crap with analogies.
What is an electron? It is mass bearing and negatively charged.
Is it a wave or a particle? It really seems to be whatever it needs to be at the moment.
It really seems to be neither.
This applies to larger things as well. If buckyballs act as a wave and we "know" that they are particles, it suggests particles themselves aren't exactly just particles.

As soon as you say "an electron is like a billiard ball", students get a mental model of the thing that is going to need to be un-learned (probably with great difficulty) at some future date, if they want to pursue the subject.
My question is, if we do a double slit experiment with billiard balls, what is the result? I mean other than using up impossible resources to scale the experiment.
 
What about this interpretation?

Quote:
''Just to clarify one point, if a single photon is fired at the two slits, an interference pattern will not appear. Rather, a single 'blip' will appear on the screen, which indicates that the photon is not a wave, but rather a particle. If a large number of photons are fired at the slits,an interference pattern will begin to appear. So it seems that photons are really particles that behave collectively like waves. The same reasoning applies to all particles, not just photons.''
 
My question is, if we do a double slit experiment with billiard balls, what is the result? I mean other than using up impossible resources to scale the experiment.

When you get to near an Avogadro’s number of particles the coherence length will be impossibly small. Now, if you can make a Bose Einstein condensate large enough it might get interesting.
 
What about this interpretation?

Quote:
''Just to clarify one point, if a single photon is fired at the two slits, an interference pattern will not appear. Rather, a single 'blip' will appear on the screen, which indicates that the photon is not a wave, but rather a particle. If a large number of photons are fired at the slits,an interference pattern will begin to appear. So it seems that photons are really particles that behave collectively like waves. The same reasoning applies to all particles, not just photons.''

I don’t like the use of the word “collectively” here. It’s not that an electron interferes with other electrons. It’s more that its wave-like properties interact with the two slits to generate the probability pattern of where the particles will be detected.
 
What about this interpretation?

Quote:
''Just to clarify one point, if a single photon is fired at the two slits, an interference pattern will not appear. Rather, a single 'blip' will appear on the screen, which indicates that the photon is not a wave, but rather a particle. If a large number of photons are fired at the slits,an interference pattern will begin to appear. So it seems that photons are really particles that behave collectively like waves. The same reasoning applies to all particles, not just photons.''

I don’t like the use of the word “collectively” here. It’s not that an electron interferes with other electrons. It’s more that its wave-like properties interact with the two slits to generate the probability pattern of where the particles will be detected.

Yet the author is saying that firing single photons does not produce an interference pattern?
 
What about this interpretation?

Quote:
''Just to clarify one point, if a single photon is fired at the two slits, an interference pattern will not appear. Rather, a single 'blip' will appear on the screen, which indicates that the photon is not a wave, but rather a particle. If a large number of photons are fired at the slits,an interference pattern will begin to appear. So it seems that photons are really particles that behave collectively like waves. The same reasoning applies to all particles, not just photons.''

I don’t like the use of the word “collectively” here. It’s not that an electron interferes with other electrons. It’s more that its wave-like properties interact with the two slits to generate the probability pattern of where the particles will be detected.

Yet the author is saying that firing single photons does not produce an interference pattern?

A single photon generates a single blip.
BUT that blip need not be located at point A (where it would fall if it passed through slit #1 specifically) nor at point B (for slit #2). Instead the blip may fall on one of the crests of the interference pattern defined by the two-slit probability wave.


HELP! I'm a fan of Huw Price's theory that quantum entanglement is the obvious outcome once time's arrow is properly understood. Bell's Theorem and the EPR and GHZ paradoxes cease to be paradoxical. Controversy about hidden variables or locality disappears. However I do not see how to use this insight to understand the 2-slit experiments. (And Huw Price didn't answer my e-mail!)
 
What about this interpretation?

Quote:
''Just to clarify one point, if a single photon is fired at the two slits, an interference pattern will not appear. Rather, a single 'blip' will appear on the screen, which indicates that the photon is not a wave, but rather a particle. If a large number of photons are fired at the slits,an interference pattern will begin to appear. So it seems that photons are really particles that behave collectively like waves. The same reasoning applies to all particles, not just photons.''

I don’t like the use of the word “collectively” here. It’s not that an electron interferes with other electrons. It’s more that its wave-like properties interact with the two slits to generate the probability pattern of where the particles will be detected.

Yet the author is saying that firing single photons does not produce an interference pattern?

A single photon cannot produce a pattern of any kind, let alone behave collectively. It's like any sort of data. A single data point doesn't form a pattern. You need lots of data points to reveal a pattern that might reflect a property of the source of the data.
 
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