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Period: 322 to
Aristotle
Hypothesised that no matter how many times you cut a form of matter in half, the result will be smaller. His views of the atomic atom lasted 2000 years -
Antoine Lavoisier
Often called the father of time. -
John Dalton
All elements are made of atoms and indivisible.
Believed atoms looked lika a ball -
Werner Heisenberg
Described atoms by means of formula connected to the frequencies of spectral lines. -
James Maxwell
Proposed electric and magnetic fields filled the void -
Marie Curie
Studied uranium and thorium and called their spontaneous decay process "radioactivity". She and her husband Pierre also discovered the radioactive elements polonium and radium. -
JJ Thomson
Used the Cathode ray tube to test atoms. Believed atoms were similar to plum pudding -
Max Planck
used the idea of quanta (discrete units of energy) to explain hot glowing matter -
Robert Millikan
Oil drop experiment determined the charge (e=1.602 x 10 -19 coulomb) and the mass (m = 9.11 x 10 -28 gram) of an electron. -
Ernst Rutherford
Had the gold foil experement. -
Henery Moseley
Using x-ray tubes, determined the charges on the nuclei of most atoms. He wrote"The atomic number of an element is equal to the number of protons in the nucleus". This work was used to reorganize the periodic table based upon atomic number instead of atomic mass. -
Neils Bohr
Believed electrons moved in orbit around the Nucleus. -
Erwin Schrodinger
Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. -
James Chadwick
Discovered the neutron -
Democritus
Greek Era. First to discover the atom. Though his visual was very plain and a basic sphere -
Modern Electron Cloud Model
