-
Original Periodic Table of elements founded
In 1862, French geologist Alexandre-Emile Béguyer de Chancourtois listed the elements on paper tape and wound them, spiral like, around a cylinder. Certain ‘threes’ of elements with similar properties came together down the cylinder. He called his model the ‘telluric screw’. -
Discovery of atomic weight by john newlands
In 1864, English chemist John Newlands noticed that, if the elements were arranged in order of atomic weight, there was a periodic similarity every 8 elements. He proposed his ‘law of octaves’ on this. -
compilation of 56 elements
In 1869, Lothar Meyer complied a periodic table of 56 elements based on a regular repeating pattern of physical properties such as molar volume. Once again, the elements were arranged in order of increasing atomic weights. -
mendeleev's Table
Also in 1869, Russian chemist Dmitri Mendeleev produced a periodic table based on atomic weights but arranged ‘periodically’. Elements with similar properties appeared under each other. Gaps were left for yet to be discovered elements. -
Discovery of the noble gases
In 1894, William Ramsay discovered the noble gases and realised that they represented a new group in the periodic table. -
creation of atomic number
In 1914, Henry Moseley determined the atomic number of each of the known elements. He realised that, if the elements were arranged in order of increasing atomic number rather than atomic weight, they gave a better fit within the ‘periodic table’. -
First artifical elements
In 1940, Glenn Seaborg artificially produced heavy mass elements such as neptunium. These new elements were part of a new block of the periodic table called ‘actinides’.
