At the start in “A quick review of atoms”, there is the following sentence with “describing” spelled wrong:
“which means we need to find eigenvalues and eigenvectors of a 6-dimensional partial differential equation, instead of a 3-dimensional one descirbing hydrogen.”
Just noticed: “filling” is spelled as “filing” twice in " Quantum numbers and shell filling"
Here: “Combining the two rules, we obtain the shell filing order”
And here: “Shell filing is important to us because the valence electrons”