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Antoine Lavoisier
Grouped the elements based on their properties into gases, non-metals, metals and earths. -
Johann Döbereiner
Recognised element in groups of three that have chemically similar properties. And showed that the properties of the middle element could be predicted from the properties of the other two. -
John Newlands
Newlands noticed that there were similarities between elements with atomic weightswith a difference of seven.He called this The Law of Octaves, drawing a comparison with the octaves of music. -
Alexandre-Emile Béguyer de Chancourtois
Alexandre-Emile Béguyer de Chancourtois invented the telluric screw that plotted the atomic weights of each element on the outside of a cylinder and when rotated there was an increase in atomic weight of 16. Although the telluric screw did not correctly display all the trends that were known at the time, de Chancourtois was the first to use a periodic arrangement of all of the known elements, showing that similar elements appear at periodic atom weights. -
Julius Lothar Meyer
1864-1870
he produced 2 periodic tables with his first one with just 28 elements listed in order of valency. In 1868 he made a much more devloped tablewith the transition metals. The 1868 table listed the elements in order of atomic weight, with elements with the same valency arranged in vertical lines, -
Dimitri Mendeleev
Mendeleev discovered the periodic table (or Periodic System, as he called it). He did so by arrangind and rearranging the elements until he realised that by arranging them in order of increasing atom weight, certain types of element regularly occurred. because of his pattern if an element appeared to be in the wrong place due to its atomic weight, he moved it to where it fit. -
Henry Moseley
He found a way to actually measure the atomic number using a newly-discoverd x-ray gun. He shot this at samples of elements and recorded the wavelengths. He used this to calculate the frequency.
