-
450 BCE
The Alchemists
They hypothesized that that small particles existed in seemingly empty space. healthresearchfunding.org/alchemists-atomic-theory-explained -
430 BCE
Democritus
Named the building blocks of matter atomos, Greek for indivisible. britannica.com/science/atom/development-of-atomic-theory -
380 BCE
Plato
He believed that there was a fifth atomic type. abyss.uoregon.edu/njs/glossary/plato.html -
Robert Boyle
He published a book called the Sceptical Chymist where he stated that "corpuscles", or particles existed in matter. cogweb.ucla.edu/earlymodern/Boyle_1661.html -
Antoine Lavoisier
He created the Law of Conservation of Mass. nature.com/scitable/knowledge/library/the-conservation-of-mass-17395478/ -
John Dalton
He proposed an idea that matter was made of indestructible building blocks. He also created the billiard ball model, hard wooden spheres. courses.lumenlearning.com/introchem/chapter/john-dalton-and-atomic-theory/ -
Amedeo Avogadro
He made a hypothesis that equal amounts of gas contain equal amounts of molecules/atoms. https://www.sciencehistory.org/historical-profile/amedeo-avogadro -
Dmitri Mendeleev
He created the periodic table that organized all the elements. khanacdemy.com/humanities/big-history-project/stars-and-elements -
JJ Thomson
He proved that all atoms have negatively charged electrons. He also created the plum pudding model, which contained negatively charged electrons floating in a soup of positive charge. khanacademy.org/science/chemistry/electronic-structure-of-atoms -
Pierre and Marie Curie
They discovered that radiation comes from atoms. atomciheritage.org/profile/marie-curie -
Albert Einstein
He proved that atoms exist through mathematics. ans.org/news/article-969/albert-einstein-and-the-most-elemantal-atomic-theory -
Robert Millikan
He proved that electrons have a negative charge through an experiment with oil. nobelprize.org/prizes/physics/1923/millikan/facts/ -
Niels Bohr
He created the solar system model, which had a positively charged nucleus with negatively electrons orbiting it. thehistoryoftheatomicmodel.weebly.com/solar-system-model.html -
Henry G J Moseley
He distinguished the atomic weight from the atomic number. Brittanica.com/biography/Henry-Moseley -
Ernest Rutherford
He hypothesized that neutrons existed. britannica.com/summary/Ernest-Rutherford -
Werner Heisenberg
He created a new theory of quantum mechanics. atomicheritage.org/profile/werner-heisenberg -
Erwin Schrodinger
He created the electron cloud model, which contained a cloud of electrons surrounding the nucleus. universetoday.com/38282/electron-cloud-model -
James Chadwick
He discovered neutrons. atomicheritage.org/profile/james-chadwick
