How have ideas about atomic structure changed through history?

The Greeks were the first to think of atoms, Democritus defined an atom as the smallest indivisible piece of matter using the idea that if you continue to cut a material in half, you must eventually reach a point where you can no longer cut it. Our modern ideas of atoms come from Dalton, who theorized that by combining atoms we make compounds. At this point very little was known about the atom's structure. When the electron was discovered, Thomson developed the plum pudding model of the atom - a ball of positive charge with negative electrons scattered throughout. However, Rutherford's gold leaf experiment proved this to be wrong and that most of the atom is empty space, with electrons surrounding a positive nucleus. Bohr's model of the atom followed, which proved to be a better match to experimental evidence - electrons orbit the nucleus at fixed energy levels. Lastly, the proton and then the neutron were discovered, accounting for the mass and charge of the nucleus.