# Confusion with Bohr's theory.

1. Jul 11, 2011

### vkash

what is angular momentum of a electron in 3d orbital.
Answer 1: d=2 angular momentum = sqrt(2(2+1))* h/2*pie

If this answer is correct then it should correct for all the conditions.so see second answer.
Answer 2: what if i say that was excited hydrogen piece then it's angular momentum can also be written as 3*h/2*pie

Both the answer are not same what is wrong. How angular momentum of one electron has two values?

2. Jul 11, 2011

### alxm

The Bohr model of the atom doesn't give the correct angular momentum.

3. Jul 11, 2011

### vkash

I was expecting for such answer i have a reply for you that is in hydrogen like species energy of all the sub shells in a shell is equal so energy of 3d should equal to 3s then what will new angular momentum in 3s.
One more thing is always try to answer question with logic. without proper logic your answer is not useful.
One thing coming in my mind as it's solution is that, Is there any thing like d orbital for hydrogen like species.

4. Jul 12, 2011

### alxm

I'm not sure what you're asking here. If you solve the Schödinger equation for the hydrogenic atom, the boundary conditions give you solutions for integer n = 1,2,3.. quantum numbers for the linear momentum, and l quantum numbers (such that 0 <= l <= n - 1) for the angular momentum, such that the states are 2l+1 degenerate. Those values of the linear momentum define a shell, those for angular momentum define a sub-shell. 3d is n=3, l=2 and 3s is n=3, l=0. If you're asking what n=3, l=1 is, then that's the 3p shell.
In the standard Bohr model, electronic states only have angular momentum, and incorrect values of it. It doesn't explain the degeneracy, or magnetic quantum number, or spin, or the fine and hyperfine interactions and many other things, it's also fundamentally at odds with real quantum mechanics; it's a semi-classical theory. The Bohr model is entirely incorrect in its physical description, it just happens to give the correct energy levels for the shells.

So where's the logic in comparing the results of theory known to be incorrect with the results derived from the theory that's known to be correct? The concept of 'orbitals' comes from the solutions to the Schrödinger equation for a hydrogenic atom, not the Bohr model.

5. Jul 12, 2011

### vkash

I want to say that if an electron is in 3d orbital in hydrogen like species then what is it's angular momentum? Which formula should i use Bohr's formula for schrodinger formula. A we know in hydrogen like species energy of 3s,3p,3d is equal so angular momentum should also equal.
From two replies it is coming as answer that Bohr's model is wrong for giving angular momentum and i should use this shrodinger formula (sqrt(l(l+1))* h/2*pie) to find angular momentum. (l is azimuthal quantum number.)