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The Alchemists' goal was to change regular items into gold. They believed in four basic elements that could change into each other with chemical reactions. They ended up discovering a lot of elements and created some important tools. Alchemy has a long history and no exact range of dates. -
He believed that atoms were formed from triangles. He also thought that the four basic elements had different base shapes. A tetrahedron was fire, an octahedron was air, a cube represents earth, and an icosahedron represents water. -
He created the theory of atomism, and he came up with the term atom. -
He created Boyle's Law which states that a volume of a gas decreases with increasing pressure and also said that the opposite is true. He also defined what an element is. -
He created The Law of Conservation of Mass, it stated that if substances change state or form, they will keep the same mass. He also realized oxygen's role in combustion. -
The Billiard Ball Model was made by John Dalton. His model said that atoms were small indivisible spherical objects, and that atoms of the same element were identical. -
He said everything is made of atoms, atoms from the same element are identical, and chemical compounds are combinations of elements. -
He distinguished the difference between a molecule and an atom. He also said how at the same temperature and at the same pressure different gasses with the same volume will have to same amount of molecules. -
He created the periodic table of elements -
He discovered the electron which showed that atoms are made up of smaller particles. -
They discovered polonium and radium. They also were able to confirm that radioactivity depends on the atoms, not the arrangements. -
The Plum Pudding Model was made by J. J. Thompson. He said that the atom was a sphere with a positive charge, and it had negative electrons inside it. This was his attempt to try and explain why atoms have no net electric charge. -
He mathematically proved that atoms actually exist. -
He was able to measure the electric charge of an electron. -
He said how atoms have a small dense nucleus that have electrons orbiting around it. -
He proposed an atom model that was different from Rutherford's. He said that electrons orbit the nucleus at certain distances, and they can only be at certain energy levels. -
The Solar System Model was made by Niels Bohr. It showed that the atom is made of a nucleus with some electrons orbiting around, similar to a solar system. -
He said how the atomic number is the number of positive charges in the nucleus, and how major properties of elements are determined by atomic number and not by atomic weight. He also identified gaps in the periodic table. -
He said that the behavior of subatomic particles are controlled by the laws of quantum mechanics which are different to the regular laws of physics. -
The Electron Cloud Model was made by Erwin Schrödinger. It shows the most probable location of electrons. You don't know for sure exactly where electrons are but they're more likely to be in certain places -
He discovered the neutron.