### Unpaired Electrons from Electron Configurations

Posted:

**Sun May 06, 2018 1:24 pm**How do you determine the number of unpaired electrons if you are given the electron configuration of an element?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=23&t=31408

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Posted: **Sun May 06, 2018 1:24 pm**

How do you determine the number of unpaired electrons if you are given the electron configuration of an element?

Posted: **Sun May 06, 2018 1:30 pm**

If you are given the electron configuration of an element, you can determine the number of unpaired electrons by drawing out the orbital diagram. Then when you fill in the levels, you can see which subshells do not have paired electrons.

I found this video helpful when I was stuck on this too: https://www.youtube.com/watch?v=gnZKiWgVHzk

Hope this helps :)

I found this video helpful when I was stuck on this too: https://www.youtube.com/watch?v=gnZKiWgVHzk

Hope this helps :)

Posted: **Sun May 06, 2018 1:30 pm**

First thing is to look at how many orbitals are in the last sub shell you are given.

For example, the last sub shell is p. P has 3 orbitals and can hold 6 electrons. Each orbital must be filled before you can pair electrons.

if it is 4p^3, then there are 3 unpaired electrons because you must spread out each electron into the 3 orbitals present in p.

If it is 4p^4, then there are 2 unpaired electrons. This is because you have filled up all three orbitals with one electron each. Since there is one leftover electron, you can pair that electron in one of the orbitals.

This means one orbital holds 2 paired electrons while the other 2 orbitals only have 1 unpaired in them.

For example, the last sub shell is p. P has 3 orbitals and can hold 6 electrons. Each orbital must be filled before you can pair electrons.

if it is 4p^3, then there are 3 unpaired electrons because you must spread out each electron into the 3 orbitals present in p.

If it is 4p^4, then there are 2 unpaired electrons. This is because you have filled up all three orbitals with one electron each. Since there is one leftover electron, you can pair that electron in one of the orbitals.

This means one orbital holds 2 paired electrons while the other 2 orbitals only have 1 unpaired in them.