-
400
Democritis
He lived in about 500 B.C during ancient Greece.
Came up with the idea that all matter contains extremely small particles that can not be divided. He called these particles atoms, he also said there were different types of properties within the atoms. -
410
Aristotle
Aristotle just like Democritus lived during 500 B.C in the Greek times.
Aristotle believed that matter didn't have a specific number of times it could be divided. Said there were only four elements, fire, water, earth, and air. When he tested these he said there were four qualities, hot, cold, dry, and wet. -
John Dalton
John Dalton discovered that gas consists of individual particles, he called these particles atoms. He believed all things are made of these atoms. He used his spare time to test his theory. He measured the masses of elements that combine when compounds form. He believed that the compounds all had something in common. -
Antoine Lavoisier
He made the first version of the law of conservation of mass, recognized and named oxygen, and hydrogen. -
Joseph Proust
Proust’s law is that chemical substances combine to form a small number of compounds, each combine in fixed proportions by weight. His beliefs were were not at first accepted but later on were. -
Joseph John Thomson
Joseph's atomic model shows there is one positively charged matter with negative charges scattered inside. He said the particles were negative because the particles inside were attracted to the positive plate. Used a tube filled with low pressure gas with a glowing beam all connected to a source of electric currents. Set a positive on top and negative plate on bottom. The beam would curve showing him the particles were negative. -
Hantaro Nagoaka
He had the same thoughts as Thomson but said an atom had a central nucleus with the negative charges called electron orbited the positive charged matter. -
Ernest Marsden
One of Rutherford's students, helped with the electronic wave. -
Neils Bohr
His theory is that the particles or electrons orbit around the positive charge like how the Earth orbits the sun. -
Louis de Brogile
Believed electrons had wave lengths. This idea was supported by Einstein. -
Ernest Rutherford
He discovered the nucleus. Also found that uranium emits faster moving particles that he called alpha particles. Used a piece of gold and shot a beam of light at it to see where it reflected first. -
Erwin Schrodinger
Came up with the Cat thought expirement. Which showed atoms decaying. -
James Chadwick
Discovered neutrons. Which he believed help stabalize the protons inside the atom's nucleus.
