Question

What is the total number of p orbitals containing one or more electrons in germanium?

The answer is 8, but why??

Answer 1

It should be 7, right? But It says 8 on the IB markscheme...

Answer 2

I believe the answer is actually eight @H2SO4 . The easiest way to see this is to write out the electronic configuration for germanium, which contains 32 electrons, by assigning them to atomic orbitals, starting at the lowest available energy and working our way up to the higher energies. Do you know how to do this?

If you do this, you'll see that Ge contains three types of filled p-orbitals.....the 2p orbitals, the 3p orbitals and the 4p orbitals. Each set contains three identical orbitals of equal energy, each capable of holding two electrons. We usually call these the px, py and pz orbitals, but that isn't really important here.


The 2p and 3p orbitals will both be completely filled and contain 6 electrons. The last set of orbitals to be filled (the highest occupied ones) will be the 4p orbitals. We have three orbitals these two electrons could go in to, so where do we put them?

Well, one of the rules we are following when doing this is something called Hund's Rule of Maximum Multiplicity. This states that when two or more orbitals of equal energy are available, electrons will look to occupy them singly before occupy them in pairs.

So, we will put the first electron into one of the empty orbitals (say the px orbital) and then put the second electron into one of the other empty orbitals (say the py orbital). Thus, if you count up the total number of filled and half-filled orbitals in Ge, it should come to 8. Make sure you understand how to write out the electronic configuration for Ge to satisfy yourself of this, if you're able to! Anyway, hope that helps you out :)