-
500 BCE
The Alchemists
They created a scientific process which would allow for the eventual discovery of the atom. https://scienceworld.wolfram.com/biography/Alchemists.html -
440 BCE
Plato
He found that the fifth atomic type must exist. http://abyss.uoregon.edu/~js/glossary/plato.html -
400 BCE
Democritus
He found the atom and came up with the name. https://plato.stanford.edu/entries/democritus/ -
Robert Boyle
He found the volume of a gas decreases with increasing pressure. https://www.sciencehistory.org/historical-profile/robert-boyle -
Antone Lavoisier
He found the total mass of products and reactants in chemical reactions. https://www.britannica.com/biography/Antoine-Lavoisier -
Billiard Ball Model
Because Dalton thought atoms were the smallest particles of matter, he envisioned them as solid, hard spheres, like billiard (pool) balls, so he used wooden balls to model them. https://flexbooks.ck12.org/cbook/ck-12-middl
e-school-physical-science-flexbook-2.0/section/3.12/primary/lesson/daltons-
atomic-theory-ms-ps/ -
John Dalton
He found that everything is composed of atoms. https://www.biography.com/scientist/john-dalton -
Amedeo Avogadro
He found that equal volumes of gas contain equal numbers of molecules. https://www.sciencehistory.org/historical-profile/amedeo-avogadro -
Dmitri Mendeleev
He discovered the periodic classification of the chemical elements. https://www.famousscientists.org/dmitri-mendeleev/ -
JJ Thompson
Discovered the electron https://www.nobelprize.org/prizes/
physics/1906/thomson/biographica -
Pierre and Marie Curie
The discovery of two new elements, radium and polonium. https://www.britannica.com/science/atom/Discovery-of-radioactivity -
Plum Pudding Model
The plum pudding model has electrons surrounded by a volume of positive charge. https://www.universetoday.com/38326/plum-pudding-model/ -
Albert Einstein
He mathematically proved the existence of atoms. https://www.ans.org/news/article-969/albert-einstein-and-the-most-elemental-atomic-theory/ -
Robert Millikan
He discovered there is a fundamental electron charge. https://courses.lumenlearning.com/chemistry
formajors/chapter/evolution-of-atomic-theory/ -
Ernest Rutherford
He discovered that the atom is mostly empty space. https://www.nobelprize.org/prizes/chemistry/
1908/rutherford/biographical/ -
Neils Bohr
He proposed the theory for the hydrogen atom. datehttp://abyss.uoregon.edu/~js/glossary/bohr_atom.html -
Solar System Model
The "solar system" model describes an atom as a central massive positive entity (the nucleus/sun) and, orbiting around it, the negative entities (the electrons/planets). https://socratic.org/questions/what-is-the-
problem-with-a-solar-system-
model-of-the-atom -
Henry G. J. Mosely
He concluded that the atomic number of positive charges in the nucleus. https://www.britannica.com/biography/Henry-Moseley -
Erwin Schrodinger
He studied the behavior of electrons within atoms. https://www.britannica.com/biography/Erwin-Schrodinger -
Electron Cloud Model
The electron cloud model says that we cannot know exactly where an electron is at any given time, but the electrons are more likely to be in specific areas. https://www.nuclear-power.com/nuclear-
power/reactor-physics/atomic-nuclear-physics
/fundamental-particles/what-is-electron-
properties-of-electron/electron-cloud/ -
Werner Heisenberg
He discovered the uncertainty principle. -
James Chadwick
He discovered that atoms have neutrons too. http://www.abcte.org/files/previews/chemistry/s1_p6.html