But further experiments showed that atoms were made of subatomic particles . The first subatomic particle to be identified was the electron, in 1898. Ten years later, Ernest Rutherford discovered that atoms have a very dense nucleus, which contains protons. In 1932, James Chadwick discovered the neutron, another particle located within the nucleus. Some of the alpha particles passed through the foil as expected, but some particles bounced back.
Alpha particles carry positive charge.
Like charges repel and opposites attract. This meant that there was a small concentration of positive charges in the atom. This model basically looks like a little solar system, where the nucleus is the Sun and the electrons orbit the nucleus like the planets orbit the Sun . The solid behavior of atoms is due to the electromagnetic repulsion of the electrons in the outer orbits. When you strike your hand on a table, the solidness you feel is an illusion caused by the electrons pushing away from the atoms of the table and the atoms of your hand.