Quantum Numbers

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605357751
Posts: 31
Joined: Wed Sep 18, 2019 12:20 am

Quantum Numbers

Postby 605357751 » Sun Nov 03, 2019 10:49 pm

I have difficulty understanding the rules of quantum numbers, can someone explain why some combinations are allowed and others are not.

State if the following combinations of quantum numbers are allowed or not in a one-electron
atom. For those that are disallowed state briefly why not.
a) n = 4, l = 3, ml = -4, ms = 0
b) n = 3, l = 3, ml = 1, ms = -1/2
c) n = 5, l = 2, ml = -3, ms = +1/2

AndreiRekesh1I
Posts: 52
Joined: Fri Aug 30, 2019 12:15 am

Re: Quantum Numbers

Postby AndreiRekesh1I » Sun Nov 03, 2019 10:51 pm

IIRC l must be at most one fewer than n in all cases, and the absolute value of ml must be at most equal to l.

zachary_nhem_4I
Posts: 57
Joined: Sat Aug 17, 2019 12:18 am

Re: Quantum Numbers

Postby zachary_nhem_4I » Sun Nov 03, 2019 10:55 pm

There are some energy levels that don't have certain orbitals. For example, for part b, the f block (l=3) exists within the 6th energy level (n=6), as a result, n = 3, l = 3, ml = 1, ms = -1/2 does not exist.

Julie Park 1G
Posts: 100
Joined: Thu Jul 25, 2019 12:15 am

Re: Quantum Numbers

Postby Julie Park 1G » Sun Nov 03, 2019 11:02 pm

ms (spin quantum number) describes the magnitude and direction that an electrons spins
ms only has two possible values: +1/2 and -1/2

therefore, there is no such thing as ms = 0

Kennedi2J
Posts: 101
Joined: Wed Sep 18, 2019 12:20 am

Re: Quantum Numbers

Postby Kennedi2J » Tue Nov 05, 2019 11:02 pm

There was also a question: How many electrons can have the following quantum numbers in an atom?
a) n=5, l=3, ml= -1 and the answer was 2 electrons
Can anyone explain why the answer is 2 electrons and not 14 since l corresponds to f orbital and f orbital can hold 14 electrons?


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