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Democritus
He is a Greek philospher who produced the thought of the first atomic theory. He studied gemoetry and travelled to different countries. Leucippus, his guru, originally came up with the theory, but Democritus elaborated on this. The theory declared that “The universe is composed of two elements: the atoms and the void in which they exist and move.” He predicted that these atoms weren't able to be destroyed because the size, shape and temprerure were always active and out of sight. -
Dalton
He was an English chemist and studied colour-blindness, due to the fact that he suffered from this. He was also a meteorologist and kept daily records of the weather for 57 years. His curiousity with atmospher and weather led him into reasearching nature of gas. which he built his atomic theory on. His theory was that all atoms are elements with identical mass and properties. Compounds are formed by two or more atoms. He said that "Atoms combine in simple whole number ratios to form compounds". -
Thomson
He was a British physicist who discovered electrons in different experiments that study nature of electric discharge. This was being investigated by different scientists at the time. In 1904, he put forward a model of the atom of positive matter which electrons are positioned by electrostatic forces. He showed the people that atoms split to smaller parts. The electron was the first particle to be discovered. -
Rutherford
He was a New Zealander physicist and he displayed an experiement ro test the plum pudding model. He discovered the atomic nucleus with the "scattering" experiment. He sent alpha particles through a sheet of foil and observed how the particles came off the gold atom. This was caused because of the hard, dense core of the nucleus of the atom. -
Bohr
He was born in Denmark and discovered radioactivity. This led to different models of the construction of atoms. He suggested a theory for the hydrogen atom based on the quantum theory. His theory explained why atoms released light fixed wavelengths. The Bohr model is used for atomic energy which is the energy from the nucleus. -
Chadwick
He was from Mancheaster, UK and was a nucleuar physicist and he discovered the neutron. When the helium nuclei was sent against the beryllium, the strong radiation was released. A hypothesis was made that electromagnetic radiation had high energy. However he could show this in a reaction. He suggested that another neutral particle might have existed in the nuclei. Neutron was then discovered.
