How does the size of the nucleus compare to the size of the space electrons have to orbit

Basically, a complete vacuum, however, don't mistake a vacuum for simply empty space. A vacuum still has what physicists call 'vacuum energy', which is thought to be an underlying field of it's own. 'Phantom Particles' can spontaneously come into existence in particle - antiparticle pairs, by borrowing energy from this field, only to be followed by immediate annihilation, even in this complete vacuum the empty space between the atomic cloud of an atom and its nucleus is just that: empty space, or vacuum. That's the simple answer, but there are a few subtleties: 1) Sub-atomic particles such as electrons, protons and neutrons need to be treated as quantum objects.