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Period: to
The Evolution of the Atom
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Democritus
400 BC Was the first to entertain the idea that everything was made up of small particles, called atoms. -
Robert Boyle
1649 - Discovered experimental science. -
Antoine Lavoiser
Developed Law of Conservation of Mass -
John Dalton
Proposed Atomic Theory. -
Dmitri Mendeleev
Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law. -
Eugen Goldstien
Used a CRT to study "canal rays" which had electrical and magnetic properties opposite of an electron. -
JJ Thompson
Determined charge to mass ratio of an electron. -
Max Planck
Used the idea of quanta (discrete units of energy) to explain hot glowing matter. -
Period: to
The Evolution of the Atom
Chem Hujer Atom Timeline -
Henry 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. -
Niels Bohr
Developed explanation of atomic structure. -
Erwin Schrodinger
Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. -
James Chadwick
Discovered the nuetron.
