Electron Configuration

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Isis_DW_3G
Posts: 102
Joined: Wed Sep 30, 2020 10:04 pm

Electron Configuration

Postby Isis_DW_3G » Sun Nov 01, 2020 9:11 pm

When doing electron configurations, do you do the 3d- first or the 4s- first? Which has the lower energy?
Thanks!

Andreas Krumbein 1L
Posts: 69
Joined: Wed Sep 30, 2020 10:00 pm

Re: Electron Configuration

Postby Andreas Krumbein 1L » Sun Nov 01, 2020 9:15 pm

4s comes first because it has a lower energy state.

Lily Anne Garcia 1C
Posts: 80
Joined: Wed Sep 30, 2020 9:55 pm

Re: Electron Configuration

Postby Lily Anne Garcia 1C » Sun Nov 01, 2020 9:16 pm

Hi! 4s is filled first and has lower energy

Melody Haratian 2J
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Re: Electron Configuration

Postby Melody Haratian 2J » Sun Nov 01, 2020 9:19 pm

Hello! When there are zero electrons occupying the 3d orbitals, 4s will have a lower energy than 3d. This means that 4s will go after 2p when writing electron configurations. However, when electrons begin to fill the 3d orbitals, then 4s will have the higher energy than 3d. Therefore, 4s will be written after 3d when writing electron configurations for elements with electrons in the 3d orbital.

After the element Ca, the 4s orbital has a higher energy than the 3d orbital, since 3d will have electrons filling it. Thus, after Ca, 4s will be written after 3d.

Nathan Tong 3G
Posts: 87
Joined: Wed Sep 30, 2020 9:49 pm

Re: Electron Configuration

Postby Nathan Tong 3G » Sun Nov 01, 2020 9:21 pm

From what I understand, once the 4s-state is filled and e- enter the 3d-state, the 3d- state has less energy and is listed first. However there are two exceptions to this, in the case of the half-full d5 state and full d10 state. Following d3s2 would be d5s1, rather than d4s2. This is because d5s1 has less energy than d4s2. Similarly, d10s1 would follow d8s2.

Micaela Estavillo
Posts: 55
Joined: Wed Sep 30, 2020 9:44 pm

Re: Electron Configuration

Postby Micaela Estavillo » Sun Nov 01, 2020 9:24 pm

4s is filled first!

Andy Hernandez
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Joined: Wed Sep 30, 2020 9:50 pm

Re: Electron Configuration

Postby Andy Hernandez » Sun Nov 01, 2020 11:33 pm

Why is 4s filled first?

Emilie_Paltrinieri_1K
Posts: 50
Joined: Wed Sep 30, 2020 10:07 pm

Re: Electron Configuration

Postby Emilie_Paltrinieri_1K » Mon Nov 02, 2020 12:24 am

4s comes before 3d, remember what the Aufbau Principle states!

Laura 3l
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Re: Electron Configuration

Postby Laura 3l » Mon Nov 02, 2020 2:30 am

Andy Hernandez wrote:Why is 4s filled first?


4s is filled first only if the 3d orbitals are not being occupied.


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