3d and 4s

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Layla Manoochehri
Posts: 29
Joined: Fri Sep 28, 2018 12:28 am

3d and 4s

Postby Layla Manoochehri » Sun Nov 04, 2018 11:17 pm

can someone explain the 3d and 4s orbital configuration conceptually? im not quite sure i understand it

Akhil Paladugu 3G
Posts: 30
Joined: Fri Sep 28, 2018 12:26 am

Re: 3d and 4s

Postby Akhil Paladugu 3G » Mon Nov 05, 2018 12:42 am

Electrons fill low energy orbitals (closer to the nucleus) before they fill higher energy ones. Where there is a choice between orbitals of equal energy, they fill the orbitals singly as far as possible.That is why the 4s orbital is filled before the 3d orbital, however when denoting these orbitals in a ground state configuration, we write the 3d orbital before the 4s orbital because when filled with electrons, the 4s orbitals have higher energy than the 3d orbitals.

404905747
Posts: 29
Joined: Fri Sep 28, 2018 12:17 am

Re: 3d and 4s

Postby 404905747 » Mon Nov 05, 2018 1:12 am

also with ions make sure to write out the ground state configuration first so that you know to remove 4s electrons before 3d.

kimberlyrose1G
Posts: 44
Joined: Fri Sep 28, 2018 12:27 am

Re: 3d and 4s

Postby kimberlyrose1G » Mon Nov 05, 2018 6:26 am

Although the s-orbital fills before the d-orbital when writing the electron configuration, we go by numerical order, that is why 3d will go before 4s

JiangJC Dis2K
Posts: 72
Joined: Fri Oct 12, 2018 12:16 am

Re: 3d and 4s

Postby JiangJC Dis2K » Mon Nov 05, 2018 8:23 am

Commenting on the other replies, remember that 4s is only higher in energy when the 3d orbital has electrons in it. If the 3d orbital is empty, then 4s has lower energy level. Also remember the exceptions Cr [Ar] 3d5 4s1 and Cu [Ar] 3d10 4s1!


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