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Newton
Newton dealt with the law of mechanics and stated that everything moves no matter the size. He could also prove this mathematically. -
Dalton
Dalton stated that different elements could be differentiated by their weight. -
G.J. Stoney
G.J. Stoney stated that some electrons conduct electricity. -
J.J. Thomson
J.J. Thomson cathode rays could be deflected by an electric field because they have a small amount of negatively charged electrons. -
Planck
Planck discovered the quantum theory and realised that all particles that have energy have heat. -
Democritus
Democritus thought the universe consisted of empty space which meant it had unlimited number of particles which were all different from each other and therefore he called them atoms. -
Period: to
Timeline of the atom
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Nagaoka
Developed the structure of an atom. -
Milikan
Conducted an oil drop experiment, to measure electric charge. By balancing the gravitational force with the electric force of the tiny droplets of oil suspended between two electric rods. After a countless droplets, and a few calculations he calculated the mass of a single electron. -
E. Rutherford
He named the nucleus and proton. Also explained radioactivity as the disintegration of atoms. -
H.G.J. Moseley
Studied the frequencies of x-rays given when electrons strike the positive side of a battery. Realised that the atomic number was equal to the positive charge of an atom. -
Bohr
Bohr model of the atom shows that electrons orbit around the nucleus. Discovered that it is the electrons on the outermost shell of an atom that determines the element’s characteristics. -
James Chadwick
Proved the existence of neutrons. Also worked on the creation of the atomic bomb.