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492 BCE
Democritus
He developed the concept of the atom. -
332 BCE
Aristotle
Developed theory that everything is made of matter. -
1400
Alchemy
A medieval version of chemistry that was considered witchcraft by most. Alchemy talked about elements relative to real chemicals. -
1492
Columbus Arrives in America
He killed a bunch of people and did nothing for the Atomic Model. -
American Revolution
America fought and argued to free themselves from Britain. -
John Dalton
Developed a theory that all matter is made up of atoms and all atoms are the same size. -
Robert Boyle
Replaced Aristotle's idea of the four elements with the idea that elements cannot be broken down into other compounds. -
American Civil War
A war between the Union and Confederacy. -
Dmitri Mendeleev
Organized Periodic Table by relative atomic mass. -
J. J. Thomson
Discovered the electron. -
Robert Millikan
Discovered the negative charge in electrons. -
Ernest Rutherford
Discovered that atoms have a nucleus and that the weight is in the nucleus. He also discovered protons and that they have a positive charge. -
Hans Geiger
Worked with Ernest Rutherford on his discovery of the nucleus. -
Niels Bohr
Created a model with neutrons and protons in the nucleus and electrons on shelves around the nucleus. -
World War I
An assassination of an Austrian Archduke led to a worldwide war, "The War to End All Wars"(not). -
James Chadwick
Discovered neutrons and their weight. -
World War II
Germany attacked Poland and the war started. US aligned themselves with Poland and a huge war lasted six years. -
Hiroshima
The US dropped atomic bombs on Japan.
