- #1
Jadaav
- 175
- 1
Hi,
Why does the 1st shell only can have 2 electrons in it ?
Also what are sub-shells ?
Why does the 1st shell only can have 2 electrons in it ?
Also what are sub-shells ?
Understanding Shells' Arrangement
- Thread starter Jadaav
- Start date
In summary, the 1st shell only can have 2 electrons in it because that is the number that is associated with the principal quantum number n=1. Sub-shells are orbitals, determined by quantum numbers in Schrodinger's equations. n is the principal quantum number that determines the shell. l has something to do with angular momentum, m is the magnetic angular quantum number.
- #2
SpectraCat
Science Advisor
- 1,402
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Jadaav said:
The Pauli exclusion principle says electrons in atoms cannot share the same 4 quantum numbers. The fact that the electrons are in the 1st shell determines 3 of them (n=1, l=0, ml=0), and there are only two possible values for the 4th quantum number (ms=+1/2 and ms=+1/2). Got it?
Well, for principal quantum numbers higher than n=1, there are multiple possibilities for the value of the angular momentum quantum number l (l=0 up to l=n-1). Each possible value of l is associated with a sub-shell: l=0 is called the s-subshell, l=1 is called the p-subshell, and so on.
- #3
Jadaav
- 175
- 1
What is the quantum number ?
and n,I and m ?
and n,I and m ?
- #4
SpectraCat
Science Advisor
- 1,402
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Jadaav said:
The quantum number is something you should already know about if you are asking the question in your original post
. Seriously though, please look that up on wikipedia to get the basics down, then come back here and ask specific questions if you are confused.- #5
ZealScience
- 386
- 5
To know that, you need to learn quantum mechanics a little bit. Sub-shells are orbitals, determined by quantum numbers in Schrodinger's equations. n is the principal quantum number that determines the shell. l has something to do with angular momentum, m is the magnetic angular quantum number.
In general, l must be less than n, while m must be equal to or less than l. In the first shell n=1 as it is the first shell, l only =0. In the second shell where n=2, l=0 or 1, so m=+1 or -1 or 0. For each set of parameters there is one orbital and in one orbital there are two electrons. Thus in first shell there is only on orbital possible, thus 2 electrons.
I hope this would help you with your question.
In general, l must be less than n, while m must be equal to or less than l. In the first shell n=1 as it is the first shell, l only =0. In the second shell where n=2, l=0 or 1, so m=+1 or -1 or 0. For each set of parameters there is one orbital and in one orbital there are two electrons. Thus in first shell there is only on orbital possible, thus 2 electrons.
I hope this would help you with your question.
- #6
Jadaav
- 175
- 1
ZealScience said:
OK, thanks I'm going to learn quantum mechanics first.
What is the arrangement of shells in an atom?
The arrangement of shells in an atom is a series of concentric energy levels or orbitals. These shells are numbered starting from the innermost shell, with the first shell being closest to the nucleus.
How many shells are there in an atom?
The number of shells in an atom depends on the element and the number of electrons it has. Generally, the number of shells increases as you move down the periodic table. For example, hydrogen has one shell, while uranium has seven.
Why do shells in an atom have different energy levels?
Shells in an atom have different energy levels because of the attraction between the negatively charged electrons and the positively charged nucleus. The further away an electron is from the nucleus, the higher its energy level will be.
What is the maximum number of electrons that can occupy a shell?
The maximum number of electrons that can occupy a shell is determined by the formula 2n^2, where n is the number of the shell. For example, the first shell can hold a maximum of 2 electrons (2 x 1^2), while the second shell can hold a maximum of 8 electrons (2 x 2^2).
How does the arrangement of shells affect the chemical properties of an element?
The arrangement of shells affects the chemical properties of an element by determining how easily its electrons can be gained or lost. Elements with full outer shells tend to be stable and less reactive, while those with partially filled outer shells are more reactive and likely to form chemical bonds with other elements.
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