electron configuration

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nicole-2B
Posts: 103
Joined: Fri Aug 30, 2019 12:18 am

electron configuration

Postby nicole-2B » Fri Oct 18, 2019 3:12 pm

Why does 3d go before 4s in the electron configuration? I learned before it was 4s then 3d.

Ruby Richter 2L
Posts: 103
Joined: Thu Jul 25, 2019 12:17 am

Re: electron configuration

Postby Ruby Richter 2L » Fri Oct 18, 2019 3:27 pm

If I understood correctly the 4s sublevel is lower in energy and that is why it is filled before the 3d sublevel because the 4s is lower in energy. However, after the 4s state is occupied the 3rd state becomes lower in energy. Because the 4s orbital then behaves as the outermost, highest energy orbital, that is where electrons are removed from first.

Jielena_Bragasin2G
Posts: 104
Joined: Sat Aug 24, 2019 12:18 am
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Re: electron configuration

Postby Jielena_Bragasin2G » Fri Oct 18, 2019 7:28 pm

Also, don't forget that Chromium and Copper have an odd configuration; Chromium is [Ar] 3d5 4s1 and Copper is [Ar] 3d10 4s1. As you can see, the 4s1 orbital is not completely filled for both elements and some say the reasoning is that this has more symmetry. This is just a good thing to remember and I hope it helps !

Jielena_Bragasin2G
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Re: electron configuration

Postby Jielena_Bragasin2G » Sat Oct 26, 2019 8:22 pm

Chromium and copper have this odd configuration because it is geometrically more symmetric for this atom which allows the atom to be more stable. Hope this helps!

Juana Abana 1G
Posts: 100
Joined: Wed Sep 18, 2019 12:15 am

Re: electron configuration

Postby Juana Abana 1G » Mon Oct 28, 2019 9:16 am

Ruby Richter 4G wrote:If I understood correctly the 4s sublevel is lower in energy and that is why it is filled before the 3d sublevel because the 4s is lower in energy. However, after the 4s state is occupied the 3rd state becomes lower in energy. Because the 4s orbital then behaves as the outermost, highest energy orbital, that is where electrons are removed from first.


Thank you this helps a lot.


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