ground state configuration set up

Moderators: Chem_Mod, Chem_Admin

505194972 3k
Posts: 27
Joined: Fri Sep 28, 2018 12:25 am

ground state configuration set up

Postby 505194972 3k » Sun Nov 04, 2018 2:28 am

So I know in lecture we have been discussing how the d orbital is written before the s. I have never understood why this is. Could someone explain why this is and does it happen every time no matter if either orbital is full? Is there ever a time when the d orbital is written after the s in the ground state figs?

Jordan Lo 2A
Posts: 85
Joined: Fri Sep 28, 2018 12:25 am

Re: ground state configuration set up

Postby Jordan Lo 2A » Sun Nov 04, 2018 7:21 am

4s has a lower energy than 3d, so we fill that first. That's also why we generally take electrons from 4s first as well

Chem_Mod
Posts: 17949
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 406 times

Re: ground state configuration set up

Postby Chem_Mod » Sun Nov 04, 2018 1:56 pm

The 4s orbital is only lower in energy before the 3d orbitals have any electrons, this is why you fill the 4s first. However, after you fill the 4s and then add one or greater electrons to the 3d, the 4s becomes the higher energy orbital due to shielding from the electrons in the 3d. So, generally, 4s < 3d in energy before the 3d has electrons, but the 4s > 3d after the 3d receives an electron(s). This is why you fill the 4s first, but also ionize it first, because its relative energy changes depending on the presence or absence of electrons.

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

Re: ground state configuration set up

Postby JiangJC Dis2K » Sun Nov 04, 2018 5:13 pm

Also make sure to remember the exceptions: Cr=[Ar]3d54s1 and Cu=[Ar]3d104s1 !!


Return to “Lewis Structures”

Who is online

Users browsing this forum: No registered users and 1 guest