Is an Atom Hollow?

An atom is the smallest piece of an element. But we can take a piece of the atom off - the electron. I can throw electrons. I can use electrons to see an atom. If I throw an electron at an atom slowly, it bounces off and I register the atom as a solid object -- This is like trying to throw a penny through a spinning bicycle wheel; the spokes get in the way. If I throw the penny fast enough (with enough energy) it can penetrate the electron cloud and see that the atom is hollow inside except for a very small clump at the center - the nucleus. There is an inward force (a centripetal force) on the electrons which are in orbit around the nucleus. It is not the gravitational force, which is very weak. It is the electrical force. If I (somehow) grab the nucleus and move it over, the electron cloud will follow the nucleus.