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410
Democritus
In 410 B.C.E Democritus hypothesized that if you break something down so much that would turn into tiny bits of matter that could not be broken down anymore. His idea was not popular because he had no experimental evidence to back it up with. -
410
Aristotle
Aristotle developed a theory that all matter is made of the four elements : fire, earth, water, air. -
Period: 410 to
The beginning of the Atomic Theory
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Period: to
Atomic Theory Takes Shape
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Robert Boyle
Robert Boyle's contribution to the atomic theory was that he helped define what the word element means. He wrote a book about how all things are not made of earth, fire, water, and air, but made of elements. -
Period: to
Atomic Thoery takes shape
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Isaac Newton
Issac Newton wrote a book about matter in terms of atoms. He viewed it as if at the beginning god made atoms and that particles were so hard that they would neer wear or break. -
Joseph Priestly
Joseph Priestly discovered the oxygen gas. He did this through a series of experiments with candles. -
Antonine Lavoisier
Antonine Lavoisier sometimes known as The Father of Modern Chemistry. He came up with something we now know as The Law of conservation of mass. -
Period: to
Into more depth of the Atmoic Theory
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John Dalton
John Daltion reconsidered a really old idea that each different element is made up of different types of atoms. He pictured atoms as little spheres but they have different properties.He also came up with the particle theory and tried to order the elements. -
Dmitri Mendeleev
Mendeleev was able to create the periodic table we now know today by grouping them by their atomic weights and similar characteristics of one another. -
J.J Thomson
J.J Thomson studied the idea that atoms might be made from a series of different particles. He experiemented with a cathode ray tube that helped him discover that atoms had negatively charged particles named electrons. -
Ernest Rutherford
Rutherford discovered the nucleus found in the center of the atom. He conducted an experiment with gold foil. He was also able to discover that the electrons surrounded the nucleus and that most of the atoms weight was found near the center. -
Niels Bohr
Bohr was able to discover that electrons surround the nuclues with a certain energy level called shells. He also discovered that electrons jump between sheels/ Bohr also came up witha diagram that shows how electrons arrange in an atom -
James Chadewick
Chadwick refined the idea of the nuclues. He discovered that the nuclues has neutral particles with it as well as positively charged particles.
