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The Alchemists layed down the foundation of the modern-day periodic table of elements. prezi.com/t50chitay12m -
Plato discovered that there is a 5th atomic type must exist which Aristotle later called "ether". abyss.uoregon.edu/js/glossary/plato -
Democritus believed that atoms were uniform, solid, hard, incompressible, and indestructible. -
Robert Boyle stated that all substances are made up of atoms. bbc.co.uk/history/historic-figures/boyle-robert.shtml -
Antoine Lavoiser determined the total mass of products own reactants in a chemical reaction is always the same. breakingatom.com/learn-the-periodic-table -
John Dalton came up with the fact that all matter was composed of atoms, indivisible and indestructible building blocks. Dalton thought atoms were the smallest particles of matter and he envisioned them as solid, hard spheres, like billiard balls, so he used wooden balls to model them. courses.lumenlearing.com/introchem/chapter https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-2.0/section/3.12/primary/lesson/daltons-atomic-theory-ms-ps/ -
He hypothesized that equal volumes of different gases contain an equal number of molecules. famousscientists.org/amedeo-avogrado -
Mendeleev jotted down the symbols for the chemical elements, putting them in order according to their atomic weights and inventing the periodic table. brittanica.com/biography/Dmitri-Mendeleev -
JJ Thompson discovered tiny negatively charged subatomic particles, also known as electrons. Thompson also created the Plum Pudding Model which had negatively-charged electrons embedded within a positively-charged "soup.". khanacademy.org/science/chemistry/ -
Pierre and Marie discovered the strongly radioactive elements known as polonium and radium. brittanica.com/science/atom/discovery-of-radioactivity -
Albert Einstein proved the existence of an atom and he also said that any liquid is made up of molecules. ans.org/news/article-969/albert-einstein -
Robert Millikan discovered that there is a fundamental electrical which is the charge of an electron. courses.lumenlearning.com/chemistryformajors.chapter -
Rutherford found out that the atom is made up of mostly empty space. Ernest Rutherford also made the Solar System Model which describes an atom as a central massive positive entity and, orbiting around it are the negative entities brittanica.com/biography/Ernest-Rutherford -
Niels Bohr determined the theory for the hydrogen atom. nobelprize.org/physics/physics/1922/bohr/facts/ -
Mosley discovered that the atomic number is the number of positive changes in the atom's nucleus. brittanica.com/biography/Henry-Mosely -
Erwin Schrödinger showed that the quantization of the hydrogen atom's energy levels that appeared in Niels Bohr's atomic model could be calculated from the Schrödinger equation. Schrödinger also created the Electron Cloud Model which shows a particular area in which an electron is likely to be. brittanica.com/biography/Erwin-Schrödinger -
Heisenberg discovered that a particle's position and momentum cannot be both known exactly. brittanica.com/biography/werner-heisenberg -
Chadwick concluded that atoms consisted of not only of protons and electrons but also neutrons. study.com/learn/lesson