Problem: How many unpaired electrons would you expect on aluminum in aluminum oxide.

FREE Expert Solution

Step 1: Recall that for a neutral element, Atomic number = # of protons = # of electrons

The atomic number of Al is 13 which means Al has 13 electrons.


The location of Al in the periodic table is shown below:



Based on the figure, Al belongs in the p-block in Period 3 so its electron configuration will contain the 3s and 3p subshells

Recall that: 

s–subshell can hold a maximum of 2 electrons

p–subshell can hold a maximum of 6 electrons

d–subshell can hold a maximum of 10 electrons

f–subshell can hold a maximum of 14 electrons


Starting from 1s, the electron configuration for Al is:


Al: 1s22s22p63s23p1



Step 2: In aluminum oxide, the charge of aluminum is +3.

The +3 charge means 3 e were lost. Therefore, we need to subtract 3 e starting from the highest energy level (3p).


The electron configuration for Al3+ is:


Al3+: 1s22s22p6


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Problem Details

How many unpaired electrons would you expect on aluminum in aluminum oxide.

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Orbital Diagrams concept. If you need more Orbital Diagrams practice, you can also practice Orbital Diagrams practice problems.