<< Chapter < Page Chapter >> Page >

The number of electrons that can be in a subshell depends entirely on the value of l size 12{l} {} . Once l size 12{l} {} is known, there are a fixed number of values of m l size 12{m rSub { size 8{l} } } {} , each of which can have two values for m s size 12{m rSub { size 8{s} } } {} First, since m l size 12{m rSub { size 8{l} } } {} goes from l size 12{ - l} {} to l in steps of 1, there are 2 l + 1 size 12{2l+1} {} possibilities. This number is multiplied by 2, since each electron can be spin up or spin down. Thus the maximum number of electrons that can be in a subshell is 2 2 l + 1 size 12{2 left (2l+1 right )} {} .

For example, the 2 s size 12{2s} {} subshell in [link] has a maximum of 2 electrons in it, since 2 2 l + 1 = 2 0 + 1 = 2 size 12{2 left (2l+1 right )=2 left (0+1 right )=2} {} for this subshell. Similarly, the 2 p size 12{2p} {} subshell has a maximum of 6 electrons, since 2 2 l + 1 = 2 2 + 1 = 6 size 12{2 left (2l+1 right )=2 left (2+1 right )=6} {} . For a shell, the maximum number is the sum of what can fit in the subshells. Some algebra shows that the maximum number of electrons that can be in a shell is 2 n 2 size 12{2n rSup { size 8{2} } } {} .

For example, for the first shell n = 1 size 12{n=1} {} , and so 2 n 2 = 2 size 12{2n rSup { size 8{2} } =2} {} . We have already seen that only two electrons can be in the n = 1 size 12{n=1} {} shell. Similarly, for the second shell, n = 2 size 12{n=2} {} , and so 2 n 2 = 8 size 12{2n rSup { size 8{2} } =8} {} . As found in [link] , the total number of electrons in the n = 2 size 12{n=2} {} shell is 8.

Subshells and totals for n = 3 size 12{n=3} {}

How many subshells are in the n = 3 size 12{n=3} {} shell? Identify each subshell, calculate the maximum number of electrons that will fit into each, and verify that the total is 2 n 2 size 12{2n rSup { size 8{2} } } {} .

Strategy

Subshells are determined by the value of l size 12{l} {} ; thus, we first determine which values of l size 12{ ital "ls"} {} are allowed, and then we apply the equation “maximum number of electrons that can be in a subshell = 2 2 l + 1 size 12{2 left (2l+1 right )} {} ” to find the number of electrons in each subshell.

Solution

Since n = 3 size 12{n=3} {} , we know that l can be 0, 1 , or 2 ; thus, there are three possible subshells. In standard notation, they are labeled the 3 s , 3 p , and 3 d size 12{3d} {} subshells. We have already seen that 2 electrons can be in an s state, and 6 in a p size 12{p} {} state, but let us use the equation “maximum number of electrons that can be in a subshell = 2 2 l + 1 size 12{2 left (2l+1 right )} {} ” to calculate the maximum number in each:

3 s has l = 0 ; thus, 2 2 l + 1 = 2 0 + 1 = 2 3 p has l = 1; thus, 2 2 l + 1 = 2 2 + 1 = 6 3 d has l = 2; thus, 2 2 l + 1 = 2 4 + 1 = 10 Total = 18 ( in the n = 3 shell )

The equation “maximum number of electrons that can be in a shell = 2 n 2 size 12{2n rSup { size 8{2} } } {} ” gives the maximum number in the n = 3 size 12{n=3} {} shell to be

Maximum number of electrons = 2 n 2 = 2 3 2 = 2 9 = 18.

Discussion

The total number of electrons in the three possible subshells is thus the same as the formula 2 n 2 size 12{2n rSup { size 8{2} } } {} . In standard (spectroscopic) notation, a filled n = 3 size 12{n=3} {} shell is denoted as 3 s 2 3 p 6 3 d 10 size 12{3s rSup { size 8{2} } 3p rSup { size 8{6} } 3d rSup { size 8{"10"} } } {} . Shells do not fill in a simple manner. Before the n = 3 size 12{n=3} {} shell is completely filled, for example, we begin to find electrons in the n = 4 size 12{n=4} {} shell.

Shell filling and the periodic table

[link] shows electron configurations for the first 20 elements in the periodic table, starting with hydrogen and its single electron and ending with calcium. The Pauli exclusion principle determines the maximum number of electrons allowed in each shell and subshell. But the order in which the shells and subshells are filled is complicated because of the large numbers of interactions between electrons.

Electron configurations of elements hydrogen through calcium
Element Number of electrons (Z) Ground state configuration
H 1 1 s 1 size 12{1s rSup { size 8{1} } } {}
He 2 1 s 2 size 12{1s rSup { size 8{2} } } {}
Li 3 1 s 2 size 12{1s rSup { size 8{2} } } {} 2 s 1 size 12{2s rSup { size 8{1} } } {}
Be 4 " 2 s 2 size 12{2s rSup { size 8{2} } } {}
B 5 " 2 s 2 size 12{2s rSup { size 8{2} } } {} 2 p 1 size 12{2p rSup { size 8{1} } } {}
C 6 " 2 s 2 size 12{2s rSup { size 8{2} } } {} 2 p 2 size 12{2p rSup { size 8{2} } } {}
N 7 " 2 s 2 size 12{2s rSup { size 8{2} } } {} 2 p 3 size 12{2p rSup { size 8{3} } } {}
O 8 " 2 s 2 size 12{2s rSup { size 8{2} } } {} 2 p 4 size 12{2p rSup { size 8{4} } } {}
F 9 " 2 s 2 size 12{2s rSup { size 8{2} } } {} 2 p 5 size 12{2p rSup { size 8{5} } } {}
Ne 10 " 2 s 2 size 12{2s rSup { size 8{2} } } {} 2 p 6 size 12{2p rSup { size 8{6} } } {}
Na 11 " 2 s 2 size 12{2s rSup { size 8{2} } } {} 2 p 6 size 12{2p rSup { size 8{6} } } {} 3 s 1 size 12{3s rSup { size 8{1} } } {}
Mg 12 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {}
Al 13 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {} 3 p 1 size 12{3p rSup { size 8{1} } } {}
Si 14 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {} 3 p 2 size 12{3p rSup { size 8{2} } } {}
P 15 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {} 3 p 3 size 12{3p rSup { size 8{3} } } {}
S 16 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {} 3 p 4 size 12{3p rSup { size 8{4} } } {}
Cl 17 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {} 3 p 5 size 12{3p rSup { size 8{5} } } {}
Ar 18 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {} 3 p 6 size 12{3p rSup { size 8{6} } } {}
K 19 " " " 3 s 2 size 12{3s rSup { size 8{2} } } {} 3 p 6 size 12{3p rSup { size 8{6} } } {} 4 s 1 size 12{4s rSup { size 8{1} } } {}
Ca 20 " " " " " 4 s 2 size 12{4s rSup { size 8{2} } } {}

Questions & Answers

what is defense mechanism
Chinaza Reply
what is defense mechanisms
Chinaza
I'm interested in biological psychology and cognitive psychology
Tanya Reply
what does preconceived mean
sammie Reply
physiological Psychology
Nwosu Reply
How can I develope my cognitive domain
Amanyire Reply
why is communication effective
Dakolo Reply
Communication is effective because it allows individuals to share ideas, thoughts, and information with others.
effective communication can lead to improved outcomes in various settings, including personal relationships, business environments, and educational settings. By communicating effectively, individuals can negotiate effectively, solve problems collaboratively, and work towards common goals.
it starts up serve and return practice/assessments.it helps find voice talking therapy also assessments through relaxed conversation.
miss
Every time someone flushes a toilet in the apartment building, the person begins to jumb back automatically after hearing the flush, before the water temperature changes. Identify the types of learning, if it is classical conditioning identify the NS, UCS, CS and CR. If it is operant conditioning, identify the type of consequence positive reinforcement, negative reinforcement or punishment
Wekolamo Reply
please i need answer
Wekolamo
because it helps many people around the world to understand how to interact with other people and understand them well, for example at work (job).
Manix Reply
Agreed 👍 There are many parts of our brains and behaviors, we really need to get to know. Blessings for everyone and happy Sunday!
ARC
A child is a member of community not society elucidate ?
JESSY Reply
Isn't practices worldwide, be it psychology, be it science. isn't much just a false belief of control over something the mind cannot truly comprehend?
Simon Reply
compare and contrast skinner's perspective on personality development on freud
namakula Reply
Skinner skipped the whole unconscious phenomenon and rather emphasized on classical conditioning
war
explain how nature and nurture affect the development and later the productivity of an individual.
Amesalu Reply
nature is an hereditary factor while nurture is an environmental factor which constitute an individual personality. so if an individual's parent has a deviant behavior and was also brought up in an deviant environment, observation of the behavior and the inborn trait we make the individual deviant.
Samuel
I am taking this course because I am hoping that I could somehow learn more about my chosen field of interest and due to the fact that being a PsyD really ignites my passion as an individual the more I hope to learn about developing and literally explore the complexity of my critical thinking skills
Zyryn Reply
good👍
Jonathan
and having a good philosophy of the world is like a sandwich and a peanut butter 👍
Jonathan
generally amnesi how long yrs memory loss
Kelu Reply
interpersonal relationships
Abdulfatai Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
Practice Key Terms 4

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, College physics -- hlca 1104. OpenStax CNX. May 18, 2013 Download for free at http://legacy.cnx.org/content/col11525/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'College physics -- hlca 1104' conversation and receive update notifications?

Ask