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100
The Alchemists
The alchemists were Aristotle and Plato, Aristole believed that the world was made of Earth, fire, water, and air, and told the people that. -
Period: 100 to
atomic timeline
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400
Plato
Plato came up with the word element in 400B.C.Plato ( and Aristotle) though everything was made up of water, fire, air, and earth.People believed them because of their eminence as philosophers. -
430
Democritus
Democritus was a Greek philospher who started to study matter. He asked "Could matter be divided into smaller and smaller pieces forever, or was there a limit to the number of times a piece of matter could be divided? " The Billiard Ball model was created around 400bc , for an atomic model. It looked like a blilliard ball. -
430
billiard ball
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Robert Boyle
He gave the definition of the element, this led to the discovery of what an element was made of. -
Antoine Lavoisier
Lavoisier discovered the law of conservation of mass, which is the first breakthrough in the study of chemical reactions. Lavoisier found that mass is conserved in a chemical reaction. -
John Dalton
English Chemist that performed a number of experiments that eventually led to the acceptance of the idea of atoms. His theory was that atoms of the same element are exactly alike.
Atoms of different elements are different and that compounds are formed by the joining of atoms of two or more elements. -
Dmitrin Medeleev
Medeleev was a Russian chemist ,which published a periodic table he also arranged the elements known at the time in order of relative atomic mass. -
J.J Thomson
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J.J Thomson
Thomson was an english scientists that provided the first hint that atoms are made from smaller particles. He proposed that atoms were made from a positively charged substance with negatively charged electrons scattered about. Thomson concluded that the negative charges came from within the atom and a particle smaller than an atom had to exist. So the atom was divisible. -
The curies
The Curie's discovered a radioactive element which they named radium.Both polonium and radium were more radioactive than uranium. -
Albert Einstiein
Albert determined that the laws of physics are the same for all non-accelerating observers. he showed that the speed of light within a vacuum is the same no matter the speed at an observer travels. -
Ernest Rutherford
Ernest rutherford was an english physicist. he was working on an experiment that involved firing a stream of tiny positively charged particles at a thin sheet of gold foil (2000 atoms thick) -
Electron Cloud
An electron cloud is a space in which electrons are likely to be found. -
Solar system model
In 1913, Neils Bohr, a student of Rutherford 's, developed a new model of the atom. -
Henry G Mosely
Henry is an English physicists whose contribution to the science of physics was the justificaton from physical laws of the previous emprical and chemiacal concept of the atomic number. -
Niels Bohr
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Niels Bohr
Nies Bohr was a Danish scientists that proposed an improvement. In the experiment he placed each electron a specific energy level.
