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Proposes the existence of tiny particles, which he called atomos, after cutting a stone into smaller and smaller pieces and deciding that at one point you will reach a point where the stone can no longer be divided.
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Comes in with the theory that all matter is made up of four elements, his influence overshadows Democritus’ theory for a couple thousand years.
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Discovers the Law of Conservation of Mass:
Mass of a chemical reaction’s products is equivalent to the mass of the starting materials. -
Dalton - Formulated the Atomic Theory of Matter based on experimental evidence.
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Discovers electrons through his experiments with the cathode ray tube.
Constructs plum-pudding model -
Discovered by J.J. Thomson - An atom is a sphere full of positively charged fluid with negatively charged electrons scattered throughout.
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Shoots alpha particles at gold foil. Most went through it and some bounced off of it. This shows that atoms are mostly empty space and that there are positive particles (protons) in the nucleus that repels the positive alpha particles.
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Determines the charge of an electron, which allowed scientists to calculate the mass of electrons.
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Based off of Rutherford's data. Similar to the structure of the solar system, hence the name, "planetary model". Consists of a positively charged nucleus surrounded by orbiting electrons.
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Proposed that electrons take the property of waves and formulated an equation to apply to all types of matter.
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Constructs the Quantum Mechanical Model: Doesn’t find the precise path of an electron, only predicts the odds of the location of an electron.
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Constructed by Werner Heisenberg, states that we cannot know the speed and position of electrons at the same time.
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Chadwick discovers a neutral particle, the neutron.
