Which Element to Use in Electron Configurations

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Drew Myers 4G
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Which Element to Use in Electron Configurations

Postby Drew Myers 4G » Sat Oct 19, 2019 9:40 pm

When doing electron configurations for multi-electron atoms, do we always use the noble gas of the previous line to shorten the configuration? Why can't we use the atom that comes before the atom we're doing the configuration for?

Sebastian Lee 1L
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Joined: Fri Aug 09, 2019 12:15 am
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Re: Which Element to Use in Electron Configurations

Postby Sebastian Lee 1L » Sat Oct 19, 2019 9:47 pm

Typically you would use the last element with a full shell (typically a noble gas) to shorthand. The problem with using the last element is that it would be confusing when identifying the extra electron in your element. For example, if I was doing the configuration for Ca, it would be weird to say [K] 4s1 because this would be like saying 1s2 2s2 2p6 3s2 3p6 4s1 4s1 (the 4s subshell is split?).

Also this could also be problematic considering the exceptions to normal configurations. For example, Cu is [Ar] 3d10 4s1 but Ni (the element right before) is [Ar] 3d8 4s2. Saying [Ni] 3d2 4s-1 is problematic.

Kavee Dodampahala 4E
Posts: 51
Joined: Sat Jul 20, 2019 12:17 am

Re: Which Element to Use in Electron Configurations

Postby Kavee Dodampahala 4E » Sat Oct 19, 2019 9:47 pm

When writing out electron configurations out, there are 2 formats you can use. The first format is writing it all out, for example the electron configuration for lithium would be writing as 1s2 2s1. The second format is naming the past noble gas before the element and just writing the configuration of the addition electrons from there, this way lithium could be written as [He]2s1.

faithkim1L
Posts: 105
Joined: Fri Aug 09, 2019 12:17 am

Re: Which Element to Use in Electron Configurations

Postby faithkim1L » Sat Oct 19, 2019 10:16 pm

When shortening the electron configuration to make it easier to sort through, people use the noble gas and write out the last line of the electron configuration. However, you can also just write out the whole thing.

Aayush Patel 3B
Posts: 51
Joined: Thu Jul 25, 2019 12:17 am

Re: Which Element to Use in Electron Configurations

Postby Aayush Patel 3B » Sat Oct 19, 2019 11:55 pm

Unless it asks for the full electron configuration of an element, noble gas configuration is an easier way to write it. The noble gas is used because they have no more room for electrons and are stable.

ZainAlrawi_1J
Posts: 71
Joined: Sat Aug 24, 2019 12:16 am

Re: Which Element to Use in Electron Configurations

Postby ZainAlrawi_1J » Sun Oct 20, 2019 12:03 am

As far as this class is concerned, always use the noble gas configuration when applicable unless otherwise indicated. It saves a lot of time and is definitely the "proper" way of doing it.


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