CHEMISTRY COMMUNITY

So p has three orbitals p(x), p(y), p(z). When filling up the electrons orbitals, does electron necessarily fill up in the order of p(x), p(y), p(z)? or just in random?

The electrons fill up in the different Px, Py, and Pz first as all up spin or down spin. If Px, Py, and Pz each have one electron spinning up, then the next three electrons will form pairs with them in the opposite direction.

I believe that Dr. Lavelle said that it is random/arbitrary since px, py, and pz can all be generalized to the p subshell.

Yes, all three orbitals can be generalized together, but like Ethan said, all three must spin up in the same direction before being paired.