The Rutherford model has a small positive nucleus at the centre and a lot of empty space. Electrons orbit the nucleus due to electrostatic attraction.
It's impossible to draw an atom without promoting misconceptions. If the nucleus were a dot the electrons wouldn´t fit on the page!
Key Concepts
The fact that positive alpha particles are deflected by a thin foil of gold atoms is evidence for the existence of a small positive nucleus. This is an example of a scientific discovery where the theory developed from an experiment.
Scattering
Analysing the path of particles (or waves) bouncing off an object is a common way to find out what that object is.
Ask a friend to place blob(s) of plasticine under a cover - you would need to roll small balls through to find out where the plasticine is located.
Summary
Nuclei are:
Heavy - since they don't move when alpha particles rebound
Positive - since they repel alpha particles
Small - since only a small number of particles are deflected