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Period: 430 BCE to 370 BCE
Democritus's Discovery of the atom
Democritus conjectured that every bit of living and non-living items were comprised of tiny little invisible particles that came in different sizes and could combine and sperate -
427 BCE
Plato's Atomic theory
he used Aristotle's atomic theory and defined all of them into shapes based on Wich ones could be broken down mathematically -
400 BCE
Democritus's Discovery of the atom
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360 BCE
Aristotle's denial of the Atomic Theory
Aristotle completely dismissed the idea of atoms and believed that everything in the universe was made from either Water, Wind, Fire, and Earth -
Lavoisier's Atomic Theory
Antoine Lavoisier is often referred to as the father of modern-day chemistry because he revolutionized chemistry with his law of conservation of mass -
John Dalton's Discovery of The Atom
John Dalton's atomic theory was the first complete attempt to try and fully describe what matter was made up of and what consisted of was a small particle, but John Dalton's Model was that of the shape of a bowling ball -
Newlands Law of Octaves
The law of octaves was proposed by an English chemist called J.A.R Newlands and he proposed one of the starting ideas for a periodic table by suggesting that all the known elements should be organized by their atomic mass, and he had seven different sections of atoms -
Mendeleev's Periodic Table
He created a periodic table but left spaces open for yet undiscovered atoms and had guessed the atomic mass and placement on the parodic table to a t -
Photoelectric Effect
Heinrich Rudolf Hertz discovered this effect in the late 1800's and it is the effect that by shining different lights at electrical currents the current will change in that aera -
The Discovery of Radioactivity
the discovery of radioactivity was one of the greatest accidents to happen in the world of physics the scientist that was responsible for this accidental discovery was Henri Becquerel after he had opened a drawer and discovered spontaneous radioactivity -
The Discovery of The Electron
With the discovery of the electron the theory that all atoms with homogenous was disproven because there was now scientific proof that showed atoms were made of sub particles -
The Plum Pudding Model
The Plum Pudding Model was what J.J Thompson describe as an atom because he had disproven the theory that atoms were solid few years prior and this is his model for his theory -
Robert Millikan's Atomic Theory
Robert found out the weight of a single electron which help contribute to the idea of protons and neutrons being in the center and electrons orbiting in a cloud around the nucleus -
Rutherford's Gold Foil Experiment
Rutherford's experiment led him to learn that the center of an atom was a positively charged core with negative particles orbiting around the nucleus like the earth orbits around the sun -
Bohr's Planetary Model
A scientist named Neils Bohr had improved upon J.J Thompson's model by making it more defined and saying that there is a nucleus full of positive and neutral particles while there are electrons orbiting in a particular path -
The Discovery of The proton
The proton was discovered by Ernest Rutherford, he found that the same particles in the nucleus of a hydrogen atom had the same particles in every single atom -
the charge of an electron
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Heisenberg's Uncertainty Principle
The principle of uncertainty was made by a scientist named Werner Heisenberg and his principle stated that by knowing where a particle is on the quantum level we do not know how fast that particler particle is going or vice versa -
Discovery of The Neutron
After thinking for a decade about the possibility of another particle in the nucleus of an atom he then started to do experiments and found that te particle called a neutron was neutral and was slightly heavier than the weight of a proton