Is the space between the electron shell and nucleus a perfect vacuum?

[saln1]

Is the space between the electron shell and nucleus a perfect vacuum?

 

[jtbell]

In general, there is no "space" between an electron shell and the nucleus. The radial probability distribution extends all the way inwards to the nucleus. See these graphs for examples:

http://hyperphysics.phy-astr.gsu.edu/Hbase/hydwf.html

 

[Dale]

jtbell is right, but also, you would have to define the term "perfect vacuum".