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aufbau principle

Posted: Sun Nov 03, 2019 11:52 pm
by Aashka Popat 1A
What is the Aufbau principle and why does the 4s subshell have lower energy than the 3d subshell?

Re: aufbau principle

Posted: Sun Nov 03, 2019 11:57 pm
by Micah3J
Will we need to know the f block for the midterm?

Re: aufbau principle

Posted: Mon Nov 04, 2019 8:06 am
by christabellej 1F
The Aufbau principle is the building up principle that combines both Pauli Exclusion principle and Hunds rule. Pauli Exclusion principle states that there can be a max of two electrons per orbital and that the two electrons must be spin paired. Hunds rule states that the electrons should be placed one per orbital first in a parallel manner. The 4s subshell only has lower energy if the 3d subshell is not filled yet. Once the 3d subshell has electrons within it, then it has lower energy than the 4s.

Re: aufbau principle

Posted: Mon Nov 04, 2019 8:58 am
by Ashley Tran 2I
Micah3J wrote:Will we need to know the f block for the midterm?


No, we need to know s, p, and d.

Re: aufbau principle

Posted: Mon Nov 04, 2019 9:57 am
by Robin Cadd 1D
Anything past the 3d block we don't need to know.