The nucleus of the atom
has a diameter of about
meter, whereas
the atomic diameter is about 
meter.
This means that the nucleus has
a diameter 10,000 times smaller than the atom. The great amount of empty space
in an atom can be illustrated by the following analogy.
Imagine the nucleus
to be the size of a golf ball. Then on this scale the first electron shell
would be about one kilometer from the golf ball, the second shell about four
kilometers, the third nine kilometers and so on. If you find that hard to
visualize then try this. The period at the end of this sentence, (depending
on your monitor and the font you are using), is probably about 1/2 a millimeter
in diameter. If that period represents the nucleus then the electrons in
the first shell would be orbiting with a diameter about 50 meters around you.
in fact, the actual diameter of an atom is very small and it would require some
two hundred million of them side by side to form a line a centimeter long.