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400 BCE
Democritus
What did Democritus do? He figured out that all matter is made up of little particles called atoms.
He did not use any experiment, he merely hypothesized it, -
Period: 400 BCE to
Times of the Atom's changes/advances
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Dalton
Made the first useful atomic theory, and is still used today with some alterations. He made this theory as he was researching gasses. -
Crookes
He found with Cathode Ray Tubes that the atom has different parts of that are negatively charged, and from that he found out that there are also some positive parts in an atom, but couldn't visualize it. This would make his theory of what it looks like a lot more advance then what it was at its own time. -
Thomson
Using Cathode Ray Tubes found out that the negative parts of the atom are Electrons. Thomson's model goes back to original models that are more simple like others before him other then Crookes which is more advance. -
Becquerel
That some atoms have radioactivity inside of them, he figured this out by experimenting with Uranium. Becquerel figuring that out has led the world to be able to make nuclear bombs. -
Rutherford
He discovered the Nucleus ofthe atom which he figured using an ingenious experiment. Which was that he shot a beam of alpha particles at a sheet of gold foil, then a few of the particle deflected against it, then seeing that he figured out that atoms have nucleates. -
Bohr
Bohr discovered that atoms circle around the nucleus of the atom. His model is used today still as the representation of the atom. He found out this idea of the atom inside of Rutherford's lab, working for Rutherford. -
Electron Cloud Model
The Electron Cloud Model was made by Erwin Schrödinger which still today we can't see just one atom but we can see Electron Cloud Model which are a cloud/group of atoms. -
Chadwick
He found out that neutrons don´t have charges but are just weight in the nucleus of the atom, he figured this out by studying Beryllium radiation. -
What Model is used today?
Bohr's Model
