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Democritus Atomic Model
Democritus lived from 460 BC to 370 BC. He was an ancient philosopher that spent a lot of his time wandering and thinking about science. His theory was that the atom were bounded together. They could not be separate. His model was sphere that is invisible. -
Dalton's Atomic Theory
Dalton was an english chemist. Dalton's theory was that all matter is made of atoms. Atoms cannot be created or broken. It is stated that all atoms of a given element are the same in mass and properties. When atom rearranges, the chemical reacts and compound are form. -
Periodic Table
Russian chemist Dimitri Mendeleev started the development of the Periodic table. He put the chemical elements by atomic mass and such. -
Eugen Goldstein
He did experiments with cathode ray tubes, which knock electrons off atoms and attract them to a positively-charged electrode (the cathode).He discovered that atoms had positive charges. -
Thomson's Plum Pudding Model
Thomson's atom is composed of electrons surrounded by postive charge to balance the electron's negative charges. So the negative charges is the "plum" and the positive charges is the "pudding" -
Rutherford's Atomic Model
Ernest Rutherford created a model of the atom. By that he used his gold-foil experiment. He found out that there is a small nucleus in the atom. He thought that the electrons in the atom, floated freely around in an electron cloud. -
James Chadwick
James Chadwick discovered the neutron. It was third type of subatomic particle. -
Atomic Bomb of Hirsoshima and Nagasaki
The atomic bombings of the cities of Hiroshima and Nagasaki in Japan was run by the United States during the final stages of World War II in 1945. These two events represent the only use of nuclear weapons in war. -
Neil Bohr's Theory
Neil Bohr took the quantum theory and applied it to Rutherford's theory. He stated that there are different energy levels. When it's given more enery, the electrons will go up high. And when there is less energy, it will go down.
