Don't Electrons in Bound States Radiate and Lose Energy?

I asked r/AskPhysics

I hear that electrons in atoms are in bound states around the nucleus, smeared out rather than a point particle. If bound electron (let's say an excited state in hydrogen-like atom), has kinetic energy.. does it still 'move' in some way, and in the process, does it not radiate and energy? Or do things happen so that electron in a bound state will remain in the same energy state unless spontaneously excited/grounded to higher/lower states?

I also hear that electrons prefer being in the lowest energy state allowed, and that the electron would be in 1s ground state, cuz it somehow has the lowest energy. The bound electron, whatever it is, is still negatively charged.. what is stopping thr thing from collapsing positive proton. Does that somehow have more energy than the ground state?

I also hear, that when approaching absolute zero, something of electron losing more and more energy, and its some zero point energy due to uncertainty that somehow keeps electron from falling. Where does this energy come from?

Also, if an electron were to "fall' into proton, would it become a neutron? The free neutron practically decays into hydrogen atom and electron antineutrino, with half life of 11 minutes. Is there something that makes the hydrogen ground state have less energy than this neutron? I ll use this opportunity to ask one more question which is; do free electrons also exist as clouds of probability, or are they somehow more stereotypically particle like? And how come the bound states have less energy than this?

I might have grasped this fundamentally wrong, so forgive me in advance for any grave misunderstandings. I'm but a curious lay person. Thank You.

....

The electrons in an atom do not loose energy, as the quantum delocalization is not a classical movement that would cause to create EM radiation.

Also there are only certain energy states allowed for the electrons (or better for the wave functions), just an electron sticking to the nucleus is not an allowed energy state. Electrons want to occupy the lowest possible energy, but they can only if the state is allowed and free (that's why electrons also have to fill up higher shells, if there are enough electrons present).

An electron can "crash" into a nucleus and convert a proton into a neutron (and a neutrino). That's called electron capture and is a form of radioactive decay. Inner electrons which have a high probability or localizing at/in the nucleus have a higher probability to cause that than outer electrons. However electron capture is only possible with nuclei that are unstable somehow by having too many protons compared to neutrons. If the nuclei cannot gain stability (or give up energy) by electron capture that's not really possible.

the quantum delocalization is not a classical movement that would cause to create EM radiation; This is the most crucial part in my opinion. The radiation happens due to the classical trajectory which emerges from decoherence with the electron's environment.

...

If bound electron (let's say an excited state in hydrogen-like atom), has kinetic energy.. does it still 'move' in some way, and in the process, does it not radiate and energy? Electron orbitals are stationary states, so you shouldn't think of it as moving or radiating.

what is stopping thr thing from collapsing positive proton? Yes it still has energy, which is why it's not just sitting in the nucleus. But if you ask where is the single most likely position for the electron, it is in fact in the nucleus!

Also, if an electron were to "fall' into proton, would it become a neutron? The free neutron practically decays into hydrogen atom and electron antineutrino, with half life of 11 minutes. Is there something that makes the hydrogen ground state have less energy than this neutron? Yes, my understanding is that electron capture is not "energetically favorable" unless there are extra protons in the nucleus. That would convert an electron and a proton into a bound neutron in the nucleus.

But it's the binding energy that makes the difference. The ground state of hydrogen has negative electric potential energy in addition to its rest energy. A free neutron just has rest energy. So without comparing the rest energies in detail, you would have to add energy to a hydrogen atom to make it worth turning into a free neutron.

Thank you. I should think of electron in ground state, as this thing that exists in some place more than others, even in places closer than a0, and not moving or radiating in classical sense. And it exists more at and around a0, rather than closer to nucleus.. because it still has energy, and its inherently not allowed to have an energy lower than this for some reason. Am I correct so far? The last paragraph, I have to read it more and do some homework.

Yes. The reason the electron can’t have lower energy is that there isn’t a stationary state, a wavefunction, that exists that has lower energy. It wouldn’t be a solution to the Schrödinger equation. Worth noting that a0 is the most likely distance from the nucleus, while the nucleus is the most likely single location. It’s comparing slightly different things: the second one is the probability of catching an electron in a tiny little box; the first one is the probability of finding it in a spherical shell. 

...

Yeah this was an unsolvable problem until quantum mechanics and the wave nature of an electron was formalized, Look at figure one here (https://courses.lumenlearning.com/suny-physics/chapter/30-6-the-wave-nature-of-matter-causes-quantization/). Think of the electron as a circular wave of even wavelengths, it cannot exist but at a specific distance from the nucleus. 

That does some oversimplifications. If you look at the wave function of the 1s orbital it actually it is actully the highest in the center of the nucleus. The reason why you dont find the electron here is that there is no space. If you look at shells going out from the center it forms a maximum at a0. https://en.m.wikipedia.org/wiki/Hydrogen_atom

Thanks, It only now registered to me that cuz of the |psi|2 r2, distribution with max prob at r=a0, and zero at r=0 even tho the prob density is highest.. and that the electron still does exist in some way even at r<a0. It just felt so wrong tho, to imagine that this positively charged thing would not be peaking as close to or at r=0. But that's illogical of me, as there might be reasons. (Actually, even in particle-in-1D-box, I don't really get how, say in the lowest state, the probability is highest in the middle and 0 at the borders, I think I don't get the first principles yet)

....

You do occasionally "find" the electron there-- it leads to the contact hyperfine interaction. Thank you, always a good day to hear of a new phenomenon :-)