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Created 4 elements, air, earth, fire, and water, which they thought they could combine to form gold. In addition, these elements helped create the periodic table. -
Proposed 5th type of atom called ether and heavenly objects are composed of it. -
Theorized that everything is made out of atoms, which are tiny and indestructible, and that your soul was also made out of these. -
Defined that an element could not be broken down, and proposed that all substances were made of something like an atom. -
Discovered through experimentation, that reactants and mass in a chemical reaction stay the same. -
Proposed all matter is made up of atoms, atoms are indivisible, indestructible, all atoms of an element have the same properties, and that atoms of different elements hold different mass. -
Model created by John Dalton showing how Dalton thought atoms were tiny hard balls that have no internals -
Proposed the idea that equal volumes of gases at the same temperature and pressure hold equal amounts of molecules. -
Created the periodic table by arranging elements in order of atomic number in groups. -
Discovered the electron and their charge to mass ratio of electrons after experimenting with cathode ray tubes. -
Discovered radioactivity doesn't rely on the arrangements of atoms but the atoms themselves. The pair also discovered the elements radium and polonium. -
A model created by JJ Thompson which presents a negatively charged electrons inside a positively charged sphere. -
Used mathematics and his theory of relativity to prove the existence of atoms. -
Proposed electricity came in the form of tiny units called electrons. Also succeeded in determining the charge of an electron. -
Disproved Thompson theory by showing atoms are mostly made of empty space. He did this by firing alpha rays at a sheet of gold foil. -
Proposed for the hydrogen atom, that electron energy levels are discrete and revolve in steady orbits. -
A model created by Neils Bohr that shows a nucleus made up of neutrons and protons, surrounded by electrons in orbits. -
Found that the difference between elements is the number of protons, which means the number of protons decides the atomic number. -
Created a wave equation that allowed you to find the energy levels of electrons in atoms, using the assumption matter is classified as particles and waves. -
Model created by Erwin Schrodinger which shows a nucleus in the middle, and an electron cloud surrounding it. -
Discovered uncertainty principle, which says a particles momentum and exact position are unknown. -
Discovered neutron after launching alpha particles at beryllium atoms and a strong unknown radiation was produced.