Bohr model of the atom

[fairylight]

What are the main flaws of the Bohr atom? does anyone know a good website that would explain them????

thanx

[insane_alien]

The bohr model of the atom can only be accurately applied to the hydrogen atom. any more electrons and it gets complicated.

[□h=-16πT]

The Bohr model only works for hydrogen, as in its derivation it uses a Coloumb potential between two point particles: a proton and an electron. It fails to account for the spin of the electron and proton, as the derivation is non-relativistic, which results in a slight, almost unoticable, discrepency between the predicted emission spectra and the actual emission spectra, known as the lamb shift.

[Connor]

yeah, and with the bohr model the electron would slowly lose energy, and would spiral into collision with the nucleus. That wouldn't be cool.

[swansont]

yeah, and with the bohr model the electron would slowly lose energy, and would spiral into collision with the nucleus. That wouldn't be cool.

 

No, that wasn't one of the failings of the Bohr model. Angular momentum was quantized, which made energy quantized. But the model couldn't account for different values of angular momentum, and had planetary orbits.

[Meir Achuz]

The bohr model of the atom can only be accurately applied to the hydrogen atom. any more electrons and it gets complicated.

The main flaw of the Bohr model was it it was just a model based on ad hoc postulates (mvr=nh, etc.) that had no justification except that it worked.

This flaw was corrected by QM, in which Bohr's postulates are derived.

[Tom Mattson]

What are the main flaws of the Bohr atom? does anyone know a good website that would explain them????

thanx

 

First of all the Bohr model is internally inconsistent. It relies on a particular solution of Maxwell's equations (Coulomb's law)' date=' and said equations imply that accelerated charges must radiate. But Bohr answered this by postulating that there were certain special nonradiating orbits, and these orbits are precisely those that can contain an integral number of deBroglie wavelengths around the circumference.

 

The people at the Stanford Encyclopedia of Philosophy cited the Bohr model as an example in their entry on Paraconsistent Logic.

 

Second, while the Bohr model does quantize orbital angular momentum, it gives the wrong quantization rule. Bohr says that [imath]L=n\hbar[/imath], whereas QM says that [imath]L=\sqrt{l(l+1)}\hbar[/imath].

 

And third, observables in the Bohr model are not operators but rather real valued algebraic expressions. Since they are just elements of [imath]\mathbb{R}[/imath] they always commute, which implies no fundamental restrictions on the compatibility of observables. For instance in Bohr's theory there is no reason that you cannot measure [imath]L_x[/imath] and [imath]L_y[/imath] simultaneously to any desired accuracy.

 

That's just what I can think of off the top of my head.