The order in which subshells are filled

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EvaLi_3J
Posts: 53
Joined: Wed Oct 02, 2019 12:16 am

The order in which subshells are filled

Postby EvaLi_3J » Sun Oct 20, 2019 11:39 am

Can anyone please explain why some subshells in higher energy levels are filled earlier than those in lower energy levels?

vpena_1I
Posts: 109
Joined: Sat Aug 24, 2019 12:15 am

Re: The order in which subshells are filled

Postby vpena_1I » Sun Oct 20, 2019 11:57 am

Are you talking about cases like chromium? I know half-full (d5) and full (d10) d sub shells have lower energy than if the electrons were spread out in different, incomplete subshells. It's the symmetry that results in a more stable electron configuration.

Mariepahos4D
Posts: 50
Joined: Sat Sep 07, 2019 12:19 am

Re: The order in which subshells are filled

Postby Mariepahos4D » Sun Oct 20, 2019 12:04 pm

Energy levels are always filled from Lower to higher. However, the 3d state doesn’t become lower in energy until after the 4s state is filled and there are electrons in the 3d state as well just due to the arrangement of electrons and electron repulsion

Brandon Valafar
Posts: 112
Joined: Sat Aug 17, 2019 12:16 am
Been upvoted: 1 time

Re: The order in which subshells are filled

Postby Brandon Valafar » Sun Oct 20, 2019 12:27 pm

If you're referring to the higher energy situation with 3d and 4s, then the rule is that if you can change from d9s2 to d10s1, or from d4s2 to d5s1, you must do so.


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