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Dalton is born in Eaglesfield, UK -
Dalton hypothesized that the law of conservation of mass and the law of definite proportions could be explained using the idea of atoms. He proposed that all matter is made of tiny indivisible particles called atoms, which he imagined as "solid, massy, hard, impenetrable, movable particles.” -
Robert Millikan is born in Morrison, USA -
Einstein is born in Ulm, Germany -
Niels Bohr is born in Copenhagen, Denmark. -
Erwin is born in Vienna, Austria -
James Chadwick is born in Bollington, UK -
Broglie is born in Dieppe, France -
Heisenberg is born in Würzburg, Germany -
- Mathematically proved the existence of atoms
- Using Planks finding explained the Photoelectric effect, where electrons are ejected when light shines on a metal
- Proposed concept of Photons
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He found this by taking 2 electrically charged drops of oil and suspended them between two metal plates where they were subjected to the downward force of gravity and upward attraction of an electrical field -
- Neils Bohr creates a new atomic model
- Proposed that an electron is found only in specific circular paths, in orbit, around the nucleus
- Each electron orbit has a fixed energy called energy levels.
- Found this information by studying the way glowing, hot hydrogen gave off light
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- Introduce the idea that particles, such as electrons, could also be described as waves
- He thought this by the way streams of electrons were reflected against crystals and spread through thin metal foils
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- Using Bohr's model he created the Quantum Mechanical Model
- Quantum Mechanical Model used these calculations to describe the behavior of electrons
- He made this by combining the equations for the behavior of waves with the de Broglie equation.
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He discovered that a particle’s position and momentum can’t be known exactly -
- Proved the existence of neutrons
- He conducted an experiment where he bombarded Beryllium with alpha particles from the natural radioactive decay of Polonium.