## ground state electron configurations

Dahriel Aron 3A
Posts: 60
Joined: Fri Sep 25, 2015 3:00 am

### ground state electron configurations

For 3.19, it asks the electron configuration for sb (3+). I put [kr] 4d10 5p2 because I thought that you take off the s orbital first, but the answer is [kr] 4d10 5s. However, in a similar problem 3.5, they say that the electron configuration for bi(3+) is [xe] 5d10 6p2 since they took off the s orbital first. Can anyone explain these conflicting answers?

Brandon Truong 2G
Posts: 29
Joined: Fri Sep 25, 2015 3:00 am

### Re: ground state electron configurations

You take off the electrons that are the farthest away from the nucleus first. The p orbital electrons are farther away from the nucleus then the s orbital electrons and in the example it is the farthest away: (Ground state of Sb is [Kr]4d10 5s2 5p3)
Sb3+ would mean taking three electrons away so that you are left with [Kr] 4d10 5s2.
As for question 3.5, the answer is [Xe] 4f14 5d10 6s2 which follows the same steps as above. I'm not sure where you are getting your answers from.
You would only get rid of the s orbital electrons if it is the farthest away from the nucleus.
Hope this helps.

Sophia Xu 3F
Posts: 21
Joined: Fri Sep 25, 2015 3:00 am

### Re: ground state electron configurations

Hi,
When u take off electrons, go in the order of np, ns, (n-1)d. Hope this helps!

Dahriel Aron 3A
Posts: 60
Joined: Fri Sep 25, 2015 3:00 am

### Re: ground state electron configurations

I'm getting my answers from the solutions manual, and they had that answer which is why I am confused. Are you suggesting that the solutions manual is wrong?

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