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John Dobereiner
John Dobereiner was the German scientist who developed the "Law of Triads" which involved grouping three elements with similar properties together in a group of three. For example, salt forming elements were grouped together. Gradually numerous other triads were discovered with various properties. -
John Newlands
John Newlands arranged the elements in order of atomic mass, proposing that every 8th element had similar properties to one another. -
Lothar Meyer
Lothar Meyer arranged the then-discovered 28 elements into 6 families according to their chemical characteristics or physical traits. However, he didn't leave gaps in his version of the table found in his book: The Modern Theory of Chemistry. -
Demitri Mendeleev
Dimitri Mendeleev created a paper wherein he demonstrated all the known elements whilst leaving spaces for undiscovered elements. This was later known as the first copy of the periodic table. -
Lord Rayleigh
Lord Rayleigh, through his study of nitrogen, discovered a heavy gas which didn't react with anything. He dubbed this element "Argon", therefore discerning the first inert element. -
William Ramsey
William Ramsey discovered numerous elements including neon, krypton and xenon, with aid from Lord Rayleigh. In addition, in 1910 he created and characterised radon -
Henry Mosely
Henry Mosely applied technologies such as X-rays to order the elements. Mosely used the various emissions an element has when X-rayed to distinguish that atomic number, and not weight, was important in the grouping and ordering of the elements. -
Glenn Seaborg
Glenn Seaborg determined how heavier elements which were far rarer fit into the periodic table. For example, both the Lanthanide and the Actinide series are under the Aluminium column due to Seaborg.
