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Atoms & Void
Democritus, from Abdera, Greece, proposed the idea of an indivisible particle, the atom. -
Mechanical Universe
Newton of England proposed the idea os a mechanical universe with small solid masses in motion. -
Atomic Theory
Dalton from Cumberland, England developed the modern atomic theory. -
Electrons
G.J. Stoney, from Ireland, propposed that electricity was made of discrete negative particles. This was the introduction of electrons. -
Protons
J.J. Thomson, born in Manchester, Great Britain, associated canal rays with protons and also determined the charge to mass ratio of an electron. -
Hot glowing matter
Max Planck, a German scientist, used Quanta to explain hot glowing matters. -
Model of atom
Nagoaka of Omera, Japan, introduced a model of the atom with rings of electrons revolving around a positively charged particle, which resembled that os Saturn's. -
Charge & Mass of an Electron
Millikan, from America, determined the charge and mass of an electron through the oil drop experiment. -
Nucleus
E. Rutherford, form New Zealand, established that nucleus was: very dense, very small and positively charged. He also established that electrons were located on the outside of nucleus. -
Atomic Numbers
H.G.J. Mosely from Weymouth, England, determined the charges on the nuclei of most atomics. He established the number of protons in the nucleus to be its atomic number and thereby, reorganised the periodic table based on protons rather than by mass. -
Atomic Structure
Bohr, from Copenhagen, Denmark, deciphered the explanation of atomic structure. He created an atomic model built up of sucessive orbital shells of electrons. -
Discovery of Neutrons
James Chadwick of Bollington, England, discovered neutrons using alpha particles. He discovered "a neutral atomic particle with a mass close to a proton." -
Change of Periodic Table Layout
Glenn Seaborg, born in Michigan, America, suggested a change to the layout of the periodic table, after he synthesised six transuriam elemnts.