Does the valance shell determine overall electron charge distribution?

[Vannay]

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.

 

[mathman]

I am no expert on the subject. However the electrons are described by wave functions and are not in fixed positions, only fixed levels. From a geometric point of view they are symmetric.

 

[dextercioby]

The charge distribution is given by the outmost electron shell, because one can think of the fully occupied inner shells as a spherical spatial extension of the nuclear charge. So yes, the 19th electron of the K atom is in the 4s energy level, and 4s charge/probability clouds look like this: spherical

http://www.meta-synthesis.com/webbook/34_qn/qn_to_pt.html