The quantum vacuum

[X-43D]

Is the vacuum between the electron orbitals and the nucleus completely empty?

 

[Kruger]

no it isn't

 

[Berislav]

no it isn't

A better answer is maybe, at least in the context void of quantum field theory

X-43D, see:

http://en.wikipedia.org/wiki/Hydrogen_atom

and

http://en.wikipedia.org/wiki/Probability_density

In QFT sense the answer is no:

http://en.wikipedia.org/wiki/Vacuum_fluctuations