I'm going over the Physics GRE and this question has me a little confused. The configuration of the potassium atom in its ground state is 1s2 2s2 2p6 3s2 3p6 4s1. The answer to which of the following is true is this statement: "Its electron charge distribution is spherically symmetrical." Is it true that the valance shell, in this case 4s, determines the overall electron charge distribution of the atom? It's my understanding that the p, d, and f shapes are not spherically symmetric so this is the only explanation I have but it does not immediately make sense to me.