If accelerating charges produce electromagnetic waves, what makes Bohr's model of the atom so different from Rutherford's? Rutherford's model had a drawback that due to the constant acceleration of the electron, EM waves would be produced and the atom would become unstable. But even in Bohr's model, the fact that there are distinct energy levels does not change the fact that the electron is revolving around the nucleus. It's still accelerating, and therefore must radiate energy! And therefore, Bohr's model would be unstable as well, right? It would be great if someone helped me out with this strange mix of thoughts.
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asked Apr 17, 2021 at 3:26
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$\begingroup$ Neither the bohr nor the rutherford model are correct. They are both wrong, in different ways. What is your point here? $\endgroup$– niels nielsenApr 17, 2021 at 3:40
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$\begingroup$ see this answer of mine physics.stackexchange.com/questions/20003/… $\endgroup$– anna vApr 17, 2021 at 8:37
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2 Answers
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But even in Bohr's model, the fact that there are distinct energy levels does not change the fact that the electron is revolving around the nucleus. It's still accelerating, and therefore must radiate energy!
In classical mechanics, yes, but atoms existed, instead of the electrons falling on the nucleus and neutralizing it. The data from Atomic spectra , the photoelectric effect, and the black body radiation forced physicists to invent quantum mechanics,because the classical theories could not explain the data.
Bohr imposed quantization ( second page)of angular momentum in order to explain the mathematical series followed by the spectra of atoms, hydrogen to start with.
Quantization of angular momentum (L) meant that only photons with energy with the difference between energy levels could radiate from the atom, instead of a continuum as classical electrodynamics imposed.
Thus L is not only conserved, but constrained to discrete values by the quantum number n. This quantization of angular momentum is a crucial result and can be used in determining the Bohr orbit radii and Bohr energies.
It was with Schrodinger's equation that the mathematical theory of quantum mechanics developed, and the electrons are not in orbits, but in orbitals, probability loci., defined by the wavefunction solutions of the quantum mechanical equations.
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$\begingroup$ And quantum mechanics, I've heard, contradicts Einstein's theories. So does this mean that all these years we haven't been able to predict the accurate structure of the atom?(Sorry if it sounds stupid, I'm not even in college yet.) $\endgroup$ Apr 17, 2021 at 11:14
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$\begingroup$ Not contradicts. The general theory of relativity is classical, no probabiities. Researchers are working to find a quantized theory that will reproduce general relativity for large masses and energies and be consistent with the atomic and particle theories, all in one framework. It is for future researchers to progress this, so maybe if you study physics you could be part of them. $\endgroup$– anna vApr 17, 2021 at 11:24
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Bohr asserted without proof that when an electron was in an orbital, it was in what he called a "stationary state" in which it could not be visualized as orbiting at all and therefore was not compelled to radiate.
He further asserted that without an energy state to occupy below the ground state, an electron in its ground state was incapable of throwing away any energy and hence taking up residence in some lower energy state.
In this manner he handwaved his way around the radiative collapse issue. Later developments provided his assertions with a firm mathematical basis.
answered Apr 17, 2021 at 3:50
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$\begingroup$ you forget his angular momentum axiom for his model. It was the imposed angular momentum quantization that generated the energy levels quantization.second page hyperphysics.phy-astr.gsu.edu/hbase/Bohr.html $\endgroup$– anna vApr 17, 2021 at 5:58
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$\begingroup$ @annav, You are the expert; if you post a more correct answer to this question I will delete mine. $\endgroup$ Apr 17, 2021 at 6:34