-
427 BCE
Plato
Plato was a greek philosopher who discovered the four atomic types in the greek periodic table: earth, water, air, and fire. https://askinglot.com/what-is-contribution-of-plato -
400 BCE
Democritus
Democritus was a greek philosopher who created the theory that the universe is made of infinite atoms. https://www.britannica.com/biography/Democritus https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-2.0/section/3.11/primary/lesson/democrituss-idea-of-the-atom-ms-ps/ -
330 BCE
Solar System model
Plato first proposed that the planets followed perfect circular orbits around the Earth. Later, Heraclides (330 B.C.) developed the first Solar System model. http://abyss.uoregon.edu/~js/ast221/lectures/lec06.html -
Antoine Lavoisier
Antoine Lavoisier was a French chemist who founded the law of conservation of mass: atoms can neither be created or destroyed. https://www.nature.com/scitable/knowledge/library/the-conservation-of-mass-17395478/ -
The Alchemists
The Alchemists laid down the foundation for the modern day periodic table. date is first know discussion about it https://prezi.com/t50cihtay12m/alchemy-and-its-contributions-to-the-atomic-theory/ -
John Dalton
John dalton was an English chemist who developed the atomic theory. https://www.britannica.com/biography/John-Dalton http://chemed.chem.purdue.edu/genchem/history/dalton.html -
Billard Ball model
The Billiard Ball model of the atom was proposed by John Dalton in 1803. https://www.cram.com/essay/The-Evolution-Of-Atoms-The-Billiard-Ball/FCUK5JMEMG -
Amedeo Avogadro
Amedeo was an Italian scientist who assigned atomic weights to 17 metallic elements. https://www.britannica.com/biography/Amedeo-Avogadro -
Dmitri Mendeleev
Dmitri was a Russian chemist who arranged all the elements were arranged in size order of atomic weight, creating his version of the periodic table. https://www.britannica.com/biography/Dmitri-Mendeleev -
JJ Thomson
JJ Thomson was a British physicist who discovered the electron and proposed a model for the structure of the atom. https://www.sciencehistory.org/historical-profile/joseph-john-j-j-thomson -
Pierre and Marie Curie
Pierre and Marie Curie were polish chemists and physicists who created the term radioactive: spontaneous emission of ionizing penetrating rays by certain atoms. https://www.britannica.com/science/atom/Discovery-of-radioactivity -
Plum Pudding model
the plum pudding model was first proposed by J.J. Thomson in 1904. https://www.electrical4u.com/thomsons-plum-pudding-model/ -
Albert Einstein
Albert Einstein was a German theoretical physicist who Mathematically proved the existence of atoms. https://www.ans.org/news/article-969/albert-einstein-and-the-most-elemental-atomic-theory/ -
Ernest Rutherford
Ernest Rutherford was a new Leland physicist who created the concept of the nuclear atom. https://www.britannica.com/biography/Ernest-Rutherford -
Robert Millikan
Robert Millikan was an American experimental physicist who precisely determined the magnitude of an electron's charge. https://www.nobelprize.org/prizes/physics/1923/millikan/facts/ -
Henry G. J. Moseley
Henry G. J. Moseley was an English physicist who discovered that the atomic number of an atom is the number of positive charges in the nucleus. https://www.britannica.com/biography/Henry-Moseley -
Niels Bohr
the quantum concept which restricts energy of a system to certain discreet values, too the problem of atomic and modular structure. https://www.britannica.com/biography/Niels-Bohr -
Electron Cloud model
The Electron cloud model is a model of an atom, and was proposed by Erwin Schrodinger in 1926. https://www.universetoday.com/38282/electron-cloud-model/ -
Werner Heisenberg
Werner Heisenberg was a German theoretical chemist who made contributions to the theory of the atomic nucleus. https://www.britannica.com/biography/Werner-Heisenberg -
James Chadwick
James Chadwick was a British physicist who discovered the neutron. https://www.atomicheritage.org/profile/james-chadwick -
Erwin Schrödinger
Erwin Schrödinger was an Austrian-Irish physicist who discovered the new productive form of the atomic theory. https://www.atomicheritage.org/profile/james-chadwick