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300 BCE
Democriticus
Proposed that everything in the world is made out of small particles called atoms -
Period: 300 BCE to
Atomic Theory
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John Dalton
Proposed the solid Sphere model -
Solid Sphere Model
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Amedeo Avogadro
Had a hypothesis of: Under the same conditions and under equal volumes of gases, the amount of particles will be the same. -
Dmitri Mendeleev
Created the periodic table -
Max Planck
Planck made the assumption that energy was made of individual units, or quanta. Which made the foundation for today's quantum theory. -
JJ Thompson
Proposed the Plum Pudding model, discovered the electron. -
Plum Pudding Model
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Albert Einstein
Proposed the Photoelectric Effect which states that when light of a certain frequency shines on a metal, electrons are emitted. -
Hans Geiger
Developed Geiger Muller Tube, part of an instrument used to measure the amount of iodizing ion radiations -
Ernest Rutherford
Discovered the nucleus, proposed the nuclear model -
Planetary Model
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Nuclear Model
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Niels Bohr
Proposed the planetary model in which an atom contained a very small charged nucleus orbited by electrons. Niels Bohr applied Max Planck’s quantum theory to the Rutherford model to come up with his famous Bohr model of the atom. -
Louis De Broglie
Had a hypothesis of: If waves can behave like particles, particles can behave like waves. -
Erwin Schrodinger
Schrodinger used equations to describe the chance of finding an electron in a certain position.This led to the creation of quantum mechanical model of the atom. -
Ernest Marsden
Contributed to the Rutherford's atomic model while experimenting with alpha particles by finding hints to the existence of neutrons. -
Quantum Mechanical Model
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Electron Cloud Model
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Werner Heisenberg
Heisenberg's uncertanity principle: Its impossible to know both position and velocity of an electron at the same time. -
James Chadwick
Discovered the Neutron -
Sources:
http://www.abcte.org/files/previews/chemistry/s1_p6.html
bozemanscience.com
atomictimeline.net
nobeliefs.com
https://atomictimeline.net/
http://www.softschools.com/timelines/atomic_theory_timeline/95/
https://prezi.com/skin6wx2a7fm/atomic-theory-timeline/
https://www.preceden.com/timelines/36919-atomic-model-timeline
