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460
Atomos
Democritus, Ancient Greek philosopher theorizes the concept of invisible "atomos" or as we know, atoms.
(Please ignore the date. Only the year is correct) -
Period: 460 to
Atoms
Timeland of Atomic discoveries -
Conservation of Mass
In 1772, Antoine Lavoisier theorized, the conservation of mass. A theory that states that all of the matter and mass we first had, we'll always have. -
Positive and Negative Charges
Benjamin Franklin, one of America's founding fathers, discovers positive and negative charges of atoms.
(Year is accurate) -
Atomic Theory
The theory developed by John Dalton, that atoms can be distinguished by their different weights. -
Definite Composition
Joseph Proust creates the law of definite composition, stating that "A compound always contains two or more elements combined in a definite proportion by mass"
(Only year is accurate.) -
Periodic Table
During the 1860's Dmitri Mendeleev created the concept for the Periodic table of elements. -
X-Ray
Wilhelm Roentgen, November 8th 1895 created--accidently--the X-Ray. -
Radioactivity
(Only month and year are accurate)Henri Becquerel, a French scientist while conducting an experiment with uranimum, discovered radioactivity. -
Electron Discovery
JJ Thompson discovers the Electron of an Atom. -
Radiation Sources
Marie and Pierre Curie, French Chemists, husband and wife, discovered radioactivity in 1898. -
Quanta
Max Planck develops the Quantum theory. That light must be emitted and absorbed in a discrete amount. A radiation formula. (Please ignore the date though the year is accurate) -
Photoeletric Effect
Albert Einstein discovered the photoelectric effect of atoms in 1905. -
Electron Charge
Robert Millikan first realized the charge of electrons through conducting various experiments. -
Atomic Number
Henry Moseley, in 1914 created atomic number concept for elements. -
Nucleaus and Radiation types
In 1918 Ernest Rutherford discovered that an atom can in fact be an Ion. -
Atomic Model
The image of the atom we know today was created by Niels Bohr in 1922. It is called the Atomic Model, (Only year is accurate) -
Electron Cloud Model
The Austrian physicist, Erwin Schrodinger creates the first model of a whole atom with interacting waves.Hence the electron cloud. (Please ignore the date but the year is accurate) -
Neutrons
James Chadwick, an English scientist discovered the nucleus of an atom. -
Atomic Fission
In 1938, Otto Hahn, Lise Meitner, and Fritz Strassmann were the first to split the atom by filling it with neutrons. -
Nuclear chain reaction
Enrico Fermi, produced the first Nuclear chain reaction in 1942.
