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### Homework Question. 2.51

Posted: Wed Oct 19, 2016 3:31 pm
"How many unpaired electrons are predicted for the ground-state configuration of each of the following atoms: a) BI ...."

How do you determine the unpaired electrons ???

### Re: Homework Question. 2.51  [ENDORSED]

Posted: Wed Oct 19, 2016 3:49 pm
In order to find the number of unpaired electrons in an atom, you first find what its highest energy orbital is, then find how many electrons are in that orbital. Then you can determine how many are paired.

Part a:

Bi is element 83. Its highest energy orbital is the p-orbital (you can find this by looking at which section it's in on the periodic table). Bismuth has 3 electrons in the p-orbital. There are three p-orbital slots: Px, Py, and Pz. Because of Hund's rule, the electrons prefer being in their own slots to sharing, even though Px, Py, and Pz can each accommodate 2 electrons. Therefore, Bi has 3 unpaired electrons.

Part d:

Ni is element 28. It reaches the d-orbital. It has 8 electrons in this orbital. There are 5 slots in a d-orbital. The first 5 electrons each inhabit one of those spots. Then, the next three begin to pair with those electrons and fill the slots because there are no empty spots left. Now 3 slots have 2 paired electrons and 2 slots have only 1 unpaired electron each. Therefore, Ni has 2 unpaired electrons.

Keep in mind that any electrons in lower energy orbitals are all paired because the orbitals are full. Because they are full, each slot has a full 2 electrons in it.

### Re: Homework Question. 2.51

Posted: Tue Oct 31, 2017 4:53 am
It also helps to draw out the Aufbau structure of the highest energy orbital to visualize this.

### Re: Homework Question. 2.51

Posted: Fri Oct 25, 2019 8:15 pm
How do you draw an aufbau structure?

### Re: Homework Question. 2.51

Posted: Sun Nov 03, 2019 4:36 pm
tiffanyteguh1C wrote:It also helps to draw out the Aufbau structure of the highest energy orbital to visualize this.

What is an Aufbau structure?