Exceptions to Electron Configuration  [ENDORSED]

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Ava Harvey 2B
Posts: 54
Joined: Fri Sep 29, 2017 7:04 am

Exceptions to Electron Configuration

Postby Ava Harvey 2B » Wed Oct 25, 2017 9:38 pm

Hi! I was just wondering if the two exceptions that Lavelle mentioned in lecture regarding electron configuration (for Copper and Chromium) continue and carry on the same pattern going down groups 6 and 11 on the periodic table. Thanks so much!

Harrison Wang 1H
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

Re: Exceptions to Electron Configuration

Postby Harrison Wang 1H » Wed Oct 25, 2017 10:11 pm

A quick google search turned out that molybdenum has the same valence electron configuration as chromium but tungsten does not, while both silver and gold have the same valence electron configuration as copper.

ConnorThomas2E
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Re: Exceptions to Electron Configuration

Postby ConnorThomas2E » Thu Oct 26, 2017 2:50 pm

I also have a follow up question to this. Is there a way to tell which of the electron configurations in groups 6 and 11 will be exceptions? and why are some exceptions but others not?

Angelica Mercado 1A
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Joined: Fri Sep 29, 2017 7:04 am

Re: Exceptions to Electron Configuration

Postby Angelica Mercado 1A » Thu Oct 26, 2017 4:45 pm

Copper and Chromium are the only exceptions to the Aufbau principle because they want to have a symmetrical distribution of electrons since this would make the elements more stable. Copper wants to have its sublevel full (3d10 instead of 3d9) and Chromium wants to keep its sublevel half-filled (3d5 instead of 3d4)- in order to achieve this stability an excited electron from the 4s orbital moves to the 3d subshell. This is achievable for these two elements because the 4s and 3d subshells are close in energy and the 4s orbital has a lot of electron repulsion so it's easier for them to remove a 4s electron.

Jasmin Tran 1J
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Joined: Thu Jul 27, 2017 3:00 am

Re: Exceptions to Electron Configuration

Postby Jasmin Tran 1J » Thu Oct 26, 2017 6:09 pm

In other words, the two exceptions are for a half-filled d5 and full d10 subshells because they have lower energy. Like Angelica said, this is to make the atom more stable. These exceptions pull one electron from the s subshell (which is the subshell that holds valence electrons in this case) and put them into the d subshell to either fill it halfway so there is one electron in each orbital or to fill it all the way so that there are two electrons in each orbital.

Annie Lieu-1H
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Re: Exceptions to Electron Configuration  [ENDORSED]

Postby Annie Lieu-1H » Sun Oct 29, 2017 3:02 pm

I agree with Angelica! But in regards to the grouping, I remember Lavelle saying in class that groups in the periodic table are grouped together because of similiar properties, and so yes the groups did have more exceptions besides Chromium and Copper. But in regards to this particular test, and in general, Chromium and Copper are the main exceptions we need to know and memorize .


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