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Introduced that ideal geometric forms serve as atoms. -
All bodies are made up of individual small atoms. -
When electrons went from an outer orbit to an inner orbit, the color of the light was dependent on the energies of the orbits. -
They believed that there were 7 base elements -
Demonstrated that matter is made up of tiny particles. -
The total mass of products and reactants in a chemical reaction is always the same. -
The Billiard Ball model is a model of the atom proposed by John Dalton. -
Proposed all matter is made up of indestructible atoms. He also calculated the first relative weights of the atom. -
Stated that equal volumes of gases at equal temperature and pressure contain the same number of particles. -
Discovery of the periodic law, which states that when elements are arranged in order of increasing atomic weight the table displays a recurring pattern of properties within groups of elements. -
Discovered radioactivity. -
Proposed the plum pudding model. -
that electrons are negatively charged subatomic particles and that atoms have no net electric charge. The plum pudding model has electrons surrounded by a volume of positive charge, like negatively charged "plums" embedded in a positively charged "pudding". -
Mathematically proved the existence of atoms and their random, ceaseless motion -
Accurate demonstration of the charge carried by an electron. -
Proposed the nuclear model of the atom based on his gold foil experiment. -
Showed the atom was a small positively charged nucleus surrounded by orbiting neutrons. -
Demonstrated that the major properties of elements are determined by the atomic number of their weight. -
Theory of quantum mechanics that describes the location of electrons as a cloud around the nucleus of an atom. -
Proved existence of neutrons.