-
427 BCE
platos contribution to atomic theory
platos atomic theory was ideal geometric forms serve as atoms and they mathematically break down into triangles his major finding was there are only 5 solid shapes whose sides are made of regular polygon -
400 BCE
Democritus atomic theory
he believed atoms were specific to the material they made and that atoms where different sizes and in constant motion. this was his major finding -
332 BCE
Aristotle
Aristotle believed that matter is fundamentally constructed out of atoms and the atoms are invisible. his major discovery was inventing the scientific method of analysis. -
Lavoisier's atomic theory
Lavoisier's theory is that matter is not created or destroyed in chemical reaction. his major discovery is the role of oxygen in combustion and respirations. -
the alchemists
the alchemist laid down the foundation the the periodic table we use now. And believed that all metals were made out of sulfur and mercury. he invented experimental techniques and equipment used by chemist today. -
john Dalton
Daltons theory was that every single atom in an element such as gold is the same every other atom in the element.
this was john Daltons major discovery -
Newton's law of octaves
its a system that calculates a chemical's mass and that's how its numbered on the periotic table. newtons major discovery's where the theory of gravitation, the nature of white light and calculus -
periodic table
Dmitri Mendeleev created frame work that now is used for the periodic table and left spaces for other elements' to be discovered. this was Dmitri's major discovery -
the discovery of radioactivity
Henri Becquerel discovery was actually and accident he opened a drawer and discovered spontaneous radioactivity. his marjor discovery was that uranium salts spontaneously emit a penetrating radiation that can register on a photographic plate -
discovery of the eclectron
J.J Thomson experiments with cathode ray tubes and it showed all atoms have little electrons that float around the atoms -
photo electric effect
Heinrich Rudolf Hertz used ultraviolet light on two metal electrodes with a voltage applied across them, the light changes the voltage -
plum pudding model
J.J Thomson had discovered that atoms are composite objects, made of pieces with positive and negative charge, and that the negatively charged electrons within the atom were very small compared to the entire atom. this was J.J Thomson's major discovery -
Robert Millikan
Robert Millikan discovered and measured the charge of an electron using negatively charged oil droplets. This was Roberts major discovery -
gold foil experiment
Rutherford's gold explement was a pices of gold with a positive charge and alpha particles went right trough it showing golds atoms are mostly empty. Ernest's major discovery was alpha and beta rays . -
Neil's Bohr's
Niels Bohr's proposed a hydrogen atom based on quantum theory that some physical quantities only take discrete values, this was Neil's major discovery -
atomic numbers
Henry Moseley observed and measured the x ray spectra of different chemical elements using diffractions crystals through this he found systematic similarities between wave lengths and atomic number. this was Henrys major discovery -
Schrodinger equation
a liner differential equation that governs the wave function of a quantum-mechanical system. major discovery was wave equation -
Heisenberg's uncertainty principle
Heisenberg's principle is a equation that can use math to predict the location of a electron. Heisenberg's major discovery was quantum mechanics in terms of matrices -
the discovery of the neutron
James Chadwick found the neutron by using a lot Beryllium with alpha particles from the natural radioactive decay of Polonium. this was his major discovery -
Planck's atomic theory
Planck's atomic theory shows atoms or molecules can absorb and emit quantities of light. his major finding was the quantum of action. -
the discovery of the proton
during a experiment Ernest Rutherford created a nuclear reaction and split the first atom witch led to the discovery of the proton. his major discovery was alpha and beta rays.
