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The alchemists were the first people to start to decipher the composition of objects. Source: prezi.com/t50cihtay12m/alchemyanditscontributionstotheatomictheory -
Democritus believed all matter was composed of small particles; atoms. He believed they were indivisible.
Source: breakingatom.com/evolutionoftheatom -
He discovered atoms of matter must derive from fundamental shapes. Source:uoregon.edu/glossary/plato -
Robert Boyle proposed elements can't be broken down into simpler substances. Source: sciencehistory.org/historicalprofile/robertboyle -
He theorized that the total mass of products and reactants in a chemical reaction are the same, so therefore created the Law of Conservation of Matter. Source: famousscienntists.org/antoinelavoiser -
Dalton proposed all matter was composed of atoms, indivisible and indestructible building blocks. This led him to believe that they were built like a billiard ball, which led him to make the Billiard Ball Model. Source:courses.lumenlearning.com/introchem/chapter/johndaltonandatomictheory -
He found that equal volumes of gases at the same temperature and pressure have equal molecules. Source: sciencehistory.org/avogadro -
He was the first person to order elements in the periodic table.
Source: breakingatom.com/learntheperiodictable -
He created the Plum Pudding Model of the atoms, using cathode tubes, and found the electron. Source: breakingatom.com/historyoftheatomicmodelthompson -
They discovered two new elements, and found rays of uranium came from the atomic structure. Source: atomicheritage.org/mariecurie -
He mathematically proved the existence of atoms.
Source: ans.org/alberteinstein -
He found the atom had a mass of positive charge at the center.
Source:britannica.com/biography/rutherford -
He found the magnitude of the electron's charge.
Source:sutori.com/developementofatomictheory -
Neils Bohr proposed that electrons move around the nucleus, but only in prescribed orbits. He also proposed the Solar System Model of the atom, which said that those same electrons orbit the nucleus of an atom like the sun in a solar system. Source: www.nobelprizes,org/prizes/physics/bohr/facts -
He found the atomic number, which is the number of positive charges in the atomic nucleus. Source: britannica.com/biography/henryMosely -
He created the electron cloud model, which said that we can't know where an electron is at any given time, but the electrons are likely to be in specific areas. The reason it is called the electron cloud model is because he said electrons were like waves, treating them like as clouds of negative charge. Source: breakingatom.com/thehistoryoftheatomicmodelschrodinger -
He developed a mathematical way of expressing the energy levels of the electrons in atoms. Source: breakingatom.com/thehistoryoftheatomicmodelheisenberg -
He discovered neutrons at the center of the atom.
Source: breakingatom.com/historyofatomicmodelchadwick