What's in the empty space between a nucleus and the electrons? I was thinking the other day about how the empty space in an atom is relatively huge, but I was wondering, is it really empty space? Originally I just assumed it was a vacuum and that was it, but that just posed more questions. Please will somebody explain to me what is in the "empty" space of an atom? Sorry if the question isn't entirely clear; I'm only 16 and just completed my GCSEs (so please try to keep the answer fairly basic)!!
 A: There is no such empty space as such in an atom. The Rutherford model of particle nature is a historic model now. After Rutherford model De broglie's hypothesis came giving us the wave nature of quantic component and how it has both particle and wave nature eg. Photon. Later on Schrödingers wave equation gave us the concept of wave function and probability distribution , which leads the conclusion that electron distribution are much more like an wave where we can find the probablity of their existence in it and they are at random can have any place.the wavefunction representing the behavior of moving particles in specified position and times describe it though in other position it's less likely to have the particle and that's why magnitude of the wave function is small else where. But No its not free space at all. I think Google answered your question with respect to Rutherford model or they have talked about forbidden zone between two energy states. 
And I think  quantum theory is not included in secondary school syllabus but in high school in (11th and 12th class) you should have the basics of quantum theory. And I can't deny if the evolution of physics from classical to quantum is to incorporate in students they have to start from the basics and history. I will recommend you to look at physics books by Halliday resnick. And if you want to start from high level go for "Quantum Physics" by Eisberg and Resnick. Though it's for under graduate students, you can understand it clearly as it covered the whole history also. And language is very lucid. But to understand it you should have idea of basic calculus. 
