Periodic Table Timeline - Jason Go 10WO

By go311

  • The Sceptical Chymist

    Robert Boyle published "The Sceptical Chymist" which distinguished between the fields of chemistry and alchemy. Included was some of the earliest recored ideas of atoms, molecules, and chemical reactions

  • Hydrogen

    Henry Cavendish discovered hydrogen. An element which he described as a colorless, odourless gas that burns and can form an explosive mixture with air.

  • Oxygen

    Carl Wilhelm Scheele and Joseph Priestly independently isolated oxygen.

  • The First comprehensive list of elements is created.

    Antoine Lavoisier made the first extensive list of elements. The list featured 33 different elements and differentiated between metals and non-metals

  • Dalton's Law

    John Dalton proposes "Dalton's Law" which describes the relationship between the different components in a mixture of gases. This discovery helped future scientists isolate a mixture of gases for individual study.

  • Elements represented by letters

    Jakob Berzelius developed a table of atomic weights and introduced letters to symbolise elements

  • Elements are Grouped

    Johann Dobereiner developed groups of 3 elements with similar properties

  • Another Periodic Table developed

    Dmitri Mendeleev produced a table based on atomic weights but arranged 'periodically' with elements with similar properties under each other. His Periodic Table included the 66 known elements organized by atomic weights.

  • Valence in the Periodic Table

    Lothar Meyer develops an early version of the periodic table, with 28 elements organized by valence

  • Periodic Table is rearranged

    John Newlands arranged the known elements in order of atomic weights & observed similarities between some elements

  • Noble Gases

    William Ramsay discovered the Noble Gases.

  • Radioactive Elements

    Marie and Pierre Curie isolated radium and polonium from pitchblende.

  • Periodic Table Arranged by Atomic Number

    Henry Moseley determined the atomic number of each of the elements and rearranged the periodic table based on atomic number.

  • Neutrons Discovered

    James Chadwick discovers neutrons, which identifies isotopes. This demonstrated why there was a discrepency between atomic number and atomic weight.

  • First Synthesised Element

    Edwin McMillan and Philip H. Abelson identify neptunium, the first synthesised element. This was discovered in the products of uranium fission.

  • Lanthanides and Actinides

    Glenn Seaborg identifies lanthanides and actinides (atomic number greater than 92) which are placed below the periodic table.