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500 BCE
The Alchemists
The Alchemists broke down the chemical composition of the 4 basic elements of their period, fire, water, earth, and wind, and made it into the Periodic Table we all know and love. They also developed the theory that matter is composed of atoms of different weights. -
427 BCE
Plato
Plato discovered that ideal geometric forms as atoms. The atoms are broke into shapes such as tetrahedron (which is fire), octahedron (which is air), icosahedron (which is water, and cube (which is earth). -
400 BCE
Democritus
Democritus created a model that stated matter consists of invisible participles of atoms. He was also the one that stated everything is composed of atoms which is only physically indivisible. -
322 BCE
Aristotle
Aristotle didn't believe the atomic theory and thought earth was made of the four elements instead of atoms. He was the reason that people didn't believe Democritus's theory back then. -
Robert Boyle
Robert Boyle proposed that elements are composed of corpuslces of various types of size that can organize themselves from different chemical substances. He also made the definition of element. -
Lavoisier
Lavoisier was the founder of the atomic model which was led by a theory of the law of conservation of mass. Lavoisier found that out through a series of experiments. -
John Dalton
John Dalton thought atoms were the smallest participles of matter, so he envision as solid, hard spheres that later became the billiard ball model. The Billiard Ball model is a atomic model that basically stats that all elements are composed of atoms. -
Dmitri Mendeleev
Mendeleev was the dude who created the first periodic table and periodic law. He made and found out about the periodic table when he was organizing elements. -
The Curies
Pierre and Marie Curie was the discovers of radioactivity. They found it out after successfully isolating the radioactive' s radium salt from the mineral pitchblende -
J.J Thomson
J.J. Thomson is the founder of the plum pudding model. It's a model that shows an atom that has a positivity charged medium (or space) with a negative charged electrons inside the medium. -
Albert Einstein
Albert Einstein was the person who proved that atoms exist, which discovered one of the most well known math things in science which is E=mc2. He discovered it with nuclear power and atomic weapons, he got into drama because of that, but a single refrigerator helped him out. -
Robert Millikan
Robert did an water drop experiment that led to him discovering that all the drops were multiples of a single number. -
Ernest Rutherford
Rutherford made a mode which described the atom as a tiny and positive charged known as a nucleus. He found it out during an gold foil experiment. -
Henry G. J. Mosely
Henry G. J. Mosely was a English physicist who contribute to the atom theory. While working in the University of Manchester, his observing and measuring of X-ray spectra of various chemical elements in crystals, he found out the relation between wave-length and atomic numbers. -
Niels Bohr
Niels Bohr proposed the solar system model (at the time, it was called the bohr model) which would show the atoms orbiting around the line like our planets. It uses negativity charged electrons with positivity charged nucleus atoms. -
Werner Heisenberg
Werner Heisenberg was the founder of the electron cloud model. The electron cloud model helps visualize the positions of electrons of a atom.