john newlands- 1863, every 8 elements similar (law of octaves). ordered due to by atomic mass. similar properties recur and intervals. not believed because some elements were in the same place. some were clearly in the wrong places (no similar chemical or physical properties).
dimitri mendeleev- 1869, a russian scientist.arranged by atomic mass but left gaps for the undiscovered due to similar properties. he ignored some atomic weights where they didnt fit. initially doubted but when new elements were discovered the properties he predicted were correct.
alexander emile beguyer de chancourtois- 1862, came up with a better idea but when his work was published his diagrams were left out.
john dalton-arranged elements in order of mass (table of elements).
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