Allowed combinations of remaining quantum numbers when n = 3

In summary, the conversation discusses an atom with a closed subshell and calculates the number of electrons present using the allowed combinations of quantum numbers m and m_{s}. The spin of an electron determines the values for m_{s} while m corresponds to the eigenvalue of operators \hat{L}_{z} and \hat{S}_{z}. The total number of electrons in the n = 3, l = 2 closed subshell is found to be 10.
  • #1
Dixanadu
254
2

Homework Statement


Hey everyone

I couldn't really fit a good description into the title. Basically here's what it is.

Consider an atom in which all the states with principal quantum number n = 3 and angular momentum quantum number l = 2 are occupied by electrons (this is called a closed subshell). List the allowed combinations of the remaining quantum numbers [itex]m,m_{s}[/itex] which are related to the eigenvalues of [itex]\hat{L}_{z},S_{z}[/itex]. Hence, how many electrons are in the n = 3, l = 2 closed subshell?


Homework Equations



Dont know of any

The Attempt at a Solution



I don't have a clue...need some help T_T
 
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  • #2
What's the spin of an electron? That determines the allowed values for ms. What's the thing that tells you what values m can take?
 
  • #3
Spin of an electron is either +1/2 or -1/2...that's [itex]m_{s}[/itex] right? as far as [itex]m[/itex] goes, is that the one that ranges from -l to +l...so it has 2l+1 values right? I just don't get what all this has to do with the eigenvalues of [itex]\hat{L}[/itex] and [itex]S_{z}[/itex]...
 
  • #4
So m is the eigenvalue corresponding to operator [itex] \hat{L}_z [/itex], and ms corresponds to [itex] \hat{S}_z [/itex].

You basically got it, now you just need to figure out which values can m and ms take together, and how many combinations there are.
 
  • #5
for m = 1/2:
m = -2, -1, 0, 1, 2

for m = -1/2
m= -2, -1, 0, 1, 2

So total is 10 electrons...?
 
  • #6
Yap that looks correct
 

FAQ: Allowed combinations of remaining quantum numbers when n = 3

What are the allowed combinations of remaining quantum numbers when n = 3?

The allowed combinations of remaining quantum numbers when n = 3 are: l = 0, 1, 2; ml = -l, -l+1, ..., l-1, l; and ms = -1/2, 1/2. This means that there are 3 possible values for l, 5 possible values for ml, and 2 possible values for ms, resulting in a total of 30 allowed combinations.

How do I determine the value of l when n = 3?

To determine the value of l when n = 3, you can use the formula l = 0, 1, ..., n-1. In this case, n = 3, so the possible values of l are 0, 1, and 2. This value of l represents the angular momentum quantum number and determines the shape of the electron's orbital.

Can the quantum numbers ml and ms have any value when n = 3?

No, the quantum numbers ml and ms have specific allowed values when n = 3. For ml, the values can range from -l to l, where l is the angular momentum quantum number. And for ms, the only possible values are -1/2 and 1/2, representing the spin of the electron.

How does the value of n affect the allowed combinations of remaining quantum numbers?

The value of n determines the maximum energy level or shell that the electron can occupy. In this case, when n = 3, the electron is in the third energy level, and the allowed combinations of remaining quantum numbers are based on this value. As n increases, the number of possible combinations also increases.

Can an electron have the same set of quantum numbers as another electron?

No, according to the Pauli exclusion principle, no two electrons can have the same set of quantum numbers. This means that each electron in an atom must have a unique combination of quantum numbers, including when n = 3. This principle helps to explain the organization of electrons in an atom's energy levels and sublevels.

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