Is there no electromagnetic force between the positively charged nucleus of an atom and the electrons?
Is there no electromagnetic force between the positively charged nucleus of an atom and the electrons?
Or in other words which forces keep electrons in orbitals and prevent it from flying away or crashing into the nucleus according to modern understanding?
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Yes, of course. That's what keeps them bound together.
The follow up question would be the opposing force which keeps them in orbit(als)? This balance of force was called the planetary model which has this shortcoming that electrons might fall into the nucleus.
If electrons actually followed such a trajectory, all atoms would act is miniature broadcasting stations. Moreover, the radiated energy would come from the kinetic energy of the orbiting electron; as this energy gets radiated away, there is less centrifugal force to oppose the attractive force due to the nucleus. The electron would quickly fall into the nucleus, following a trajectory that became known as the "death spiral of the electron". According to classical physics, no atom based on this model could exist for more than a brief fraction of a second.
I am trying to recall what kind of forces enable the orbitals of electrons according to Quantum Mechanics.
Here is an explanation from part of that site:
Summed up best as:
What this means is that within the tiny confines of the atom, the electron cannot really be regarded as a "particle" having a definite energy and location, so it is somewhat misleading to talk about the electron "falling into" the nucleus.
the electron cannot really be regarded as a "particle" having a definite energy and location, so it is somewhat misleading to talk about the electron "falling into" the nucleus
Good way to put it. And if I recall correctly, electrons in "s" orbitals actually do spent a certain fraction of their time inside the nucleus.
As I understand it, it's the quantum part of quantum mechanics.
Electrons can only have fixed energy states, they can only radiate or accept fixed sized packets of energy - a "quantum" of energy. So an electron that is hit with the correct sized quantum of energy can be excited up to the next orbital, and it will emit the same sized packet of energy when it returns to its ground state. So they can't gradually emit radiation and fall into the nucleus.
Eventually electrons should spontaneously decay but that's predicted to be in 10 to the power of 40 years or something like that.
electrons should spontaneously decay
Really? What is it hypothesized that they decay into?
I looked it up, after 6.6 x 10e28 years or so they are theorised to decay into neutrinos and photons.
Six hundred and sixty octillion years. That research is going to be hard to fund.
Huh, interesting. So would charge not be conserved in that process? Neither neutrinos nor photons are charged.
Charge conservation would indeed be violated, which is why this decay is not expected. Dave is mistaken: the half-life they're referring to is an experimental lower-bound, not a actual expected value.
Thanks, that makes more sense.
Presumably there is a transformation of charge to energy which is then carried away by the photon, but all of this is beyond my understanding of the theories involved.
Charge conservation would unambiguously be violated, which is why this decay is not expected. The half-life you quote is an experimental lower-bound.
They are not expected to decay. The half-life they're thinking of is a lower-bound based on current measurements, not an actual expected half-life.
There's kind of alot going on, but the shortest answer is "the electrostatic force between the positive nucleus and negative electron creates orbits in the same way that gravity allows a moon to orbit a planet". The electron is moving fast enough that it just "misses" the nucleus. At least, from a classical lens.
It gets more complicated when you introduce orbital angular momentum and start considering the magnetic effects of moving charges, and that's what leads to the funky non-spherical orbital shapes.
And it's not like they experience air resistance to slow them down.