-
427 BCE
Plato
Plato theorized that solid forms of matter are composed of invisible elements shaped like triangles. -
400 BCE
Democritus
Democritus theorized that atoms where specific to the material they composed. -
Robert Boyle
Robert discovered that the volume of gas is inversely proportional to its pressure. -
The Alchemists
The Alchemists believed that all metals were formed from 2 principles. Mercury and sulfur. -
Antone Lavoisier
Antone defined the laws of conservation of mass/ discovered mass is neither created or destroyed in chemical reactions. -
Billiard Ball Model
Created in the early 1800 by John Dalton. -
John Dalton
Johns atomic theory was that all matter was made up of indestructible / invisible atoms. -
Amedeo Avogadro
Avogadro discovered equal volumes of gas contain equal numbers of molecules. -
Dmitri Mendeleev
Dmitri invented the periodic table. -
JJ Thompson
JJ discovered the electron. -
Pierre and Marie Currie
They discovered radioactive elements such as radium. -
Plum Pudding Model
Created by Thomas Thomson In 1904. -
Albert Einstein
Albert mathematically proved the existence of atoms. -
Robert Millikan
Robert discovered the accurate determination of the charge carried by an electron. -
Ernest Rutherford
Ernest established that most of the weight of atoms is concentrated in the nucleus. -
Henry G.J Mosely
Henry discovered positive charge in the nucleus of an atom/atomic number. -
Neils Bohr
Neils proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus. -
Solar System Model
Created in 1913 by Neils Bohr. -
Electron Cloud Model
Created by Erin Schrödinger in 1926 and by Werner Heinsberg. -
James Chadwick
James discovered the neutron.