The periodic table in its recognisable form was presented to the Russian Chemical Society in 1869 by the chemist Dmitri Mendeleev, though the paper was read for him by his colleague Nikolai Menshutkin. Mendeleev arranged the known elements by increasing atomic weight and noticed that their chemical properties recurred at regular intervals. Where the pattern broke, he left gaps and predicted that undiscovered elements would fill them, giving detailed descriptions of their properties. These forecasts were confirmed when gallium was found in 1875, scandium in 1879 and germanium in 1886. Other chemists, such as Lothar Meyer, proposed similar tables, but Mendeleev's boldness gave him the greater credit. In 1913 Henry Moseley showed that the true basis of the order is atomic number, and the table now contains 118 elements.
Before and after
- 1869Founding of Boston University
- 9 January 1869Birth of Grigori Rasputin
- from 27 January 1869 to 27 June 1869Republic of Ezo
- 14 February 1869Birth of Charles Thomson Rees Wilson
- 6 March 1869Periodic table
- 8 March 1869Death of Hector Berlioz
- 18 March 1869Birth of Neville Chamberlain
- 20 March 1869Publication of Twenty Thousand Leagues Under the Sea
- 6 April 1869Founding of American Museum of Natural History
More in Science & technology
- 1766Discovery of hydrogen
- 1771Discovery of oxygen
- 1772Discovery of nitrogen
- 1789Discovery of carbon
- 1825Discovery of aluminium
- 18 August 1868Discovery of helium
The era
This moment belongs to the Industrial era (1760 CE to 1914 CE), steam, factories and revolutions. You can also browse everything in the 19th century.