Development of the periodic table

Events

(1817) Johann Dobereiner proposed the law of triads

1817

(1862) Alexandre-Émile Béguyer de Chancourtois shows that similar elements appear at periodic atom weights

1862

(1864) Lothar Meyer had just discovered valency and periodic behabiour

1864

(1864) John Newlands put forward is law of octaves. Each element was similar to the element eight places further on.

1864

(1869) Dmitiri Mendeleev arranged the elements known at the time in order of relative atomic mass to form the periodic table

1869

(1894) Lord Rayleigh discovered the first inert gas and how to seperate compounds

1894

(1898) William Ramsay discovered a previously unknown class of inert, rare, or noble gases

1898