Download Periodic Table Timeline

Periodic Table Timeline
440 BC
Democritus and Leucippus
propose the idea of the
atom, an indivisible particle
that all matter is made of
360 BC
Plato coins the term
“elements”
330 BC
Aristotle proposes the four
element theory:
earth, air, fire and water
1605
Sir Francis Bacon published
“The Proficience and
Advancement of Learning”
which contained a description
of what would be known as
the Scientific Method
1649
Hennig Brand becomes the
first known discoverer of
an element, phosphorus,
from distilled human urine.
1661
Robert Boyle distinguishes
between chemistry and
alchemy.
1661
He also discusses some of the
earliest ideas of atoms, molecules,
and chemical reactions marking the
beginning of the history of modern
chemistry.
1766
Henry Cavendish discovered
hydrogen.
1773-1774
Carl Wilhelm Scheele and
Joseph Priestly
independently isolated
oxygen.
1778
Antoine Lavoisier wrote the
first extensive list of
“elements” containing 33
elements and distinguished
between metals and nonmetals.
1778
(Some of his “elements”
were later determined to
be compounds and included
both heat and light.)
1803
John Dalton proposes the
four principles of the
modern atomic theory.
1826
Jakob Berzelius developed a
table of atomic weights and
introduced letters to
symbolize elements.
1829
Johann Dobereiner developed
groups of three elements
with similar properties (called
triads.)
1864
John Newlands arranged the
elements in order of atomic
weights and observed
similarities between some
elements.
1864
He developed the
“Law of Octaves.”
1864
Lothar Meyer develops an
early version of the periodic
table with 28 elements
organized by valence.
1869
Dmitri Mendeleev produced a
table based on atomic weights
but arranged “periodically” with
elements of similar properties
under each other.
1869
His periodic table included
the 66 known elements.
1894
William Ramsay discovered
the noble gases.
1898
Marie and Pierre Curie
isolated radium and polonium
from pitchblende.
1913
Henry Moseley determined
the atomic number of each of
the elements and modified
the “Periodic Law.”
1940
Edwin McMillan and Philip H.
Abelson identify neptunium, the
lightest and first synthesized
transuranium element, found in
the products of uranium fission.
1941
Glenn Seaborg synthesized
and investigated 10
transuranium elements (the
elements after uranium on
the periodic table.)