Chemistry timeline. Web 2.0

  • 440

    Democritus

    Democritus speculates about fundamental indivisible particles—calls them "atoms"
  • Henry Cavendish

    Henry Cavendish ' >://en.wikipedia.org/wiki/Henry_Cavendish' >Henry Cavendish</a> </a>discovers and studies hydrogen
  • Carl Scheele and Antoine Lavoisier

  • Joseph Priestley

    Joseph Priestley creates water by igniting hydrogen and oxygen
  • William Nicholson and Anthony Carlisle

    William Nicholson and Anthony Carlisle use electrolysis to separate water into hydrogen and oxygen
  • John Dalton

    John Dalton introduces atomic ideas into chemistry and states that matter is composed of atoms of different weights
  • Thomas Young

    Thomas Young conducts Double-slit experiment (approximate time)
  • Amedeo Avogadro

    Amedeo Avogadro claims that equal volumes of gases should contain equal numbers of molecules
  • Michael Faraday

  • Dmitri Ivanovich Mendeleev

    Dmitri Ivanovich Mendeleev systematically examines the periodic table and predicts the existence of gallium, scandium, and germanium
  • Johannes van der Waals

    Johannes van der Waals introduces the idea of weak attractive forces between molecules
  • Johann Balmer

    Johann Balmer finds a mathematical expression for observed hydrogen line wavelengths
  • Heinrich Hertz

    Heinrich Hertz discovers the photoelectric effect
  • Lord Rayleigh and William Ramsay

    Lord Rayleigh and William Ramsay discover argon by spectroscopically analyzing the gas left over after nitrogen and oxygen are removed from air
  • William Ramsay

    William Ramsay discovers terrestrial helium by spectroscopically analyzing gas produced by decaying uranium
  • Antoine Becquerel

    Antoine Becquerel discovers the radioactivity of uranium
  • Pieter Zeeman

  • J.J. Thomson

    J.J. Thomson discovers the electron
  • William Ramsay and Morris Travers

    William Ramsay and Morris Travers discover neon, and negatively charged beta particles
  • Paul Villard

    Paul Villard discovers gamma-rays while studying uranium decay
  • Johannes Rydberg

    Johannes Rydberg refines the expression for observed hydrogen line wavelengths
  • Max Planck

    Max Planck states his quantum hypothesis and blackbody radiation law
  • Philipp Lenard

    Philipp Lenard observes that maximum photoelectron energies are independent of illuminating intensity but depend on frequency
  • Theodor Svedberg

    Theodor Svedberg suggests that fluctuations in molecular bombardment cause the Brownian motion
  • Albert Einstein

    Albert Einstein explains the photoelectric effect
  • Charles Barkla

    Charles Barkla discovers that each element has a characteristic X-ray and that the degree of penetration of these X-rays is related to the atomic weight of the element
  • Hans Geiger and Ernest Marsden

    Hans Geiger and Ernest Marsden discover large angle deflections of alpha particles by thin metal foils
  • Ernest Rutherford and Thomas Royds

    Ernest Rutherford and Thomas Royds demonstrate that alpha particles are doubly ionized helium atoms
  • Ernest Rutherford

    Ernest Rutherford explains the Geiger-Marsden experiment by invoking a nuclear atom model and derives the Rutherford cross section
  • Jean Perrin

    Jean Perrin proves the existence of atoms and molecules
  • Max von Laue

    Max von Laue suggests using crystal lattices to diffract X-rays
  • Walter Friedrich and Paul Knipping

    Walter Friedrich and Paul Knipping diffract X-rays in zinc blende
  • William Henry Bragg and William Lawrence Bragg

    William Henry Bragg and William Lawrence Bragg work out the Bragg condition for strong X-ray reflection
  • Henry Moseley

    Henry Moseley shows that nuclear charge is the real basis for numbering the elements
  • Niels Bohr

    NNiels Bohr presents his quantum model of the atom
  • Robert Millikan

    Robert Millikan measures the fundamental unit of electric charge
  • Johannes Stark

    Johannes Stark demonstrates that strong electric fields will split the Balmer spectral line series of hydrogen
  • James Franck and Gustav Hertz

    James Franck and Gustav Hertz observe atomic excitation
  • Ernest Rutherford

    Ernest Rutherford suggests that the positively charged atomic nucleus contains protons
  • Arnold Sommerfeld

    Arnold Sommerfeld develops a modified Bohr atomic model with elliptic orbits to explain relativistic fine structure
  • Gilbert N. Lewis and Irving Langmuir

    Gilbert N. Lewis and Irving Langmuir formulate an electron shell model of chemical bonding
  • Albert Einstein

    Albert Einstein introduces the idea of stimulated radiation emission
  • Alfred Landé

    Alfred Landé introduces the Landé g-factor
  • Arthur Compton

    Arthur Compton studies X-ray photon scattering by electrons
  • Otto Stern and Walther Gerlach

    Otto Stern and Walther Gerlach show "space quantization"
  • Louis de Broglie

    Louis de Broglie suggests that electrons may have wavelike properties
  • Lise Meitner

    Lise Meitner discovers the Auger process
  • John Lennard-Jones

    John Lennard-Jones proposes a semiempirical interatomic force law
  • Satyendra Bose and Albert Einstein

    Satyendra Bose and Albert Einstein introduce Bose-Einstein statistics
  • Wolfgang Pauli

    Wolfgang Pauli states the quantum exclusion principle
  • Linus Pauling

    discovers resonance bonding and uses it to explain the high stability of symmetric planar molecules
  • John Cockcroft and Ernest Walton

    John Cockcroft and Ernest Walton split lithium and boron nuclei using proton bombardment
  • 1933 Max Delbruck

  • Irène Joliot-Curie and Frédéric Joliot

  • Enrico Fermi

  • Large Hadron Collider