LAVOSIER
Discovered 33 elements and differentiated it into 4 groups.
5 gases_ oxygen,hydrogen,nitrogen,light,heat.
17 elements_ Antimony,silver,arscenic,bismuth,cobalt,copper,tin,iron,manganeese,mercury,molybdenium,nickel,gold,platinum,lead,zinc,tungsten.
Nonmetals_ sulphur,phosphorus,coal,chlorine,fluorine,boron.
5 metal oxides_ magnesium,alumina,silica,lime,beritta
DOBEREINER(1829)
Law of Triads Dobereiner arranged the elements of
similar properties in group of three called triads.
Döbereiner triads.mp4
JOHN NEWLANDS (1865)
Law of Octaves Newlands arranged the elements in
the order of increasing atomic weights. He noticed that every succeeding eighth element repeated the properties of the first like the eighth note on an octave in music.
John Alexander Reina Newlands.mp4
DMITRI MENDELEEV
Periodic law published. Periodic table proposed based on the
periodicity of elements. Here elements are arranged on the basis of
atomic mass.