Modern physics

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Why the rutherford atomic model can't explain the line spectra of the hydrogen atom?
 

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  • #2
malawi_glenn
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the most essential is that a spiralling charge will emit radiation and thus loose energy making the atom collapse.
 
  • #3
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But,that only explains the unstability of atom.The question is about the spectra.
 
  • #4
malawi_glenn
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if the atom is unstable, will there be a spectra? Well, it will be continuous -> compare with bremsstrahlung spectra.
 
  • #5
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So,Can I say this-Because the atom is spiralling down towards the nucleus,it will continuoulsly be giving the radiation forming a single wavelength,continuous spectra.
 
  • #6
malawi_glenn
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I would not say that it will forming a single wavelenght, that is a discrete spectrum. Your sentence is a self contradiction.
 
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So,how do I explain the reason then..........
 
  • #8
malawi_glenn
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you just drop the "forming a single wavelength" part.
 
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How about this-Rutherford's model suggests that the electrons can float around at any energy level they want, and that photons of any frequency or wavelength can be emitted.
 
  • #10
malawi_glenn
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no electrons can not float around as they want! The rutherford model is a classical, non-quantum, model where electrons are orbiting the nuclei as planets orbiting the sun.

But the electrons are then under a radial acceleration, centripetal acceleration, and accelerating charges will emit radiation of continuous spectrum - there will be no stable energy levels and no atom will be stable.
 
  • #11
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So it means that they are continuously giving radiation of same type in rutherford which give a continuous radiation.
 
  • #12
malawi_glenn
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the radiation is continuous in time and in wavelength
 
  • #13
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Thanks mate,are there any links that you know which has got the lectures on bohr's model of atom along with rutherford's and sommerfield's.
 
  • #15
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Why the orbit energy in bohr model is negative?
 
  • #16
malawi_glenn
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all bound states has negative energy. (It all boils down to where you define the 0 level of energy).
 
  • #17
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What is meant by bound states?
 
  • #18
malawi_glenn
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have you not done classical mechanics with planetary orbits and stuff? :O

roughly speaking, a system is bound if it's kinetic energy in the centre of mass system is smaller than the potential energy.
 
  • #19
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Thanks
 
  • #20
malawi_glenn
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and since one often counts potential energy as negative, the energy of a bound system will become negative.
 
  • #21
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Really appreciate all your labour mate.
 
  • #22
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Why the Rutherford atomic model can't explain the line spectra of the hydrogen atom?
In a certain approximation, it can. If your electron starts falling from infinity (or just from very distant place), it radiates a quasi-continuous spectrum. This is called a radiative recombination. But it stops falling into the potential well before reaching the nucleus: its "lowest" orbit is determined with quantum mechanics. In fact, the electron can be captured by the nucleus in some cases (http://en.wikipedia.org/wiki/K-capture). In this sense, it can "reach" the nucleus and form a neutral particle with a proton.

Bob.
 
  • #23
malawi_glenn
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But electron capture is a quantum mechanical property and has nothing to do with an electron 'spiralling' down towards the nucleus etc.
 

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