Aristotle disagreed with that idea and said that empty space doesn't exist and all matter is made from fire, water, air, and earth.
Democritus and Aristotle
Democritus said that atoms were small objects that make up everything. They can't be created or destroyed. He believed in empty space in atoms.
Proposed the Atomic Theory. Dalton agreed with Democritus' ideas. He developed an atomic model.
He did the Cathode Ray experiment. He shot a beam and it attracted to a positively charged plate. Because of how magnets work, he assumed that their must be negatively charged particles because opposites attract. He made the "Cookie" model.
He did the gold foil experiment. He did a similar experiment to J.J. Thompson. He found that some of the particles also repelled and opposites repel so it has positively charged parts as well. He made the Rutherford model which had a positive center with negative particles floating around it.
James Chadwick discovered that atoms had a nucleus that contained positive and neutral particles.
Proposed that electrons moved in a circular motion. He discovered energy levels. He found that the electrons closest to the nucleus had less power. He developed the popular "Bohr model."
Stated that electrons do NOT move in set paths but instead in waves. He said that there was electron clouds. He developed the modern atomic model.