Timeline on periodic table
Category: Outro
Atualizado: 14 jan 2019
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Created byoliver revis
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Antoine Lavoisier
defined an element
as a substance that
cannot be broken down
into a simpler
substance, by a chemical
reactioin. Lavoisier started
to classify the elements:
oxygen, nitrogen,
hydrogen, phosphorous,
mercury, zinc and sulphur,
into the groups of metals
and non-metals.Antoine LavoisierJakob BerzeliousJacob Berzelius is
credited with identifying
the chemical elements
silicon, selenium, thorium,
cerium, lithium and
vanadium. he also
developed a system of
chemical notation in which
the elements were given
simple written labels—such
as O for oxygen, or Fe for
iron—with proportions
noted by numbersJohann DobereinerJohann Dobereiner's
triads were an early
attempt to sort the
elements into some
logical order. He also
noted that some
quantifiable properties
of elements (e.g. atomic
weight and density)
in a triad followed a
trend whereby the
value of the middle
element in the triad
would be exactly or
nearly predicted by
taking the arithmetic
mean of values for
that property of the
other two elements.Alexandre-Emile
Beguyer de
ChancourtoisAlexandre-Emile Beguyer
de Chancourtois
published
his classification
of the elements.
The resulting
helical curve, which
de Chancourtois called
a square circle triangle,
brought similar
elements onto
corresponding
points above or
belowone another
on thecylinder.
He was the first
scientist to see
the periodicity
of elements when
they were arranged
in order of their
atomic weights.Dimitri MendeleevNewlands was the
first person to
devise a periodic
table of elements
arranged in order
of their relative
atomic masses.
Continuing Johann
Wolfgang Döbereiner's
work with triads. It
ultimately helped him
publish his 'Law of
Octaves', which stated
that 'any given
element will exhibit
analogous behaviour
to the eighth element
following it in the table.Henry MoseleyHenry Moseley's discovery showed
that atomic numbers were not
arbitrarily assigned, but rather,
they have a definite physical basis.
Moseley postulated that each
successive element has a nuclear
charge exactly one unit greater
than its predecessor. Moseley
redefined the idea of atomic
numbers to help sort the elements
into an exact sequence of ascending
atomic numbers that made the
Periodic Table exact.John NewlandsDimitri Mendeleev saw in a
dream a table where all
elements fell into place as
required. Awakening, he
immediately wrote it down
on a piece of paper, only in
one place did a correction
later seem necessary. By
adding additional elements
following this pattern,
Mendeleev developed his
extended version of the
periodic table.
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