Download HISTORY OF THE PERIODIC TABLE

HISTORY OF THE PERIODIC TABLE
I GREEKS (400 B.C.) – used the words “element” and
“atom”.
II Antoine Lavoisier (1700’s) – divided the element into 4
Classes
III Dobereiner (1800’s) – noted the similar elements
often had relative atomic masses
A.E. Beguyer de Chancourtois – created a cylindrical
table of elements to display the periodic
reoccurrence of properties
IV Cannizaro – determined atomic weights for
60 or so elements
V John Newlands – arranged the table with the elements
given a serial number in order of
atomic weight
- made evident “eighth element,
starting from a given one, is a kind of
repetition of the first” (Law of
Octaves)
VI DMITRI MENDELEEV(Mendeleyev)
– published his periodic table & law (1869)
– forecast the properties of missing elements
VII “MODERN PERIODIC TABLE” – arranged according
to size of the atomic weight but with
group 0 added by Ramsay
MOSELY – reordered the table according to
atomic numbers (nuclear charge)
rather than weight.
VIII HARRY HUBBARD (1924) published the modernized
Medeleyev’s periodic table called “Periodic
Chart of the Atoms”
IX 1930 Glenn Seaborg – “plucked out” the heaviest
Elements (Actinide series & Lanthanide series)
X ROY ALEXANDER – designed a three-dimensional
Periodic chart (1994) retains the separate
Lanthanide and Actinide series.
HOW DOES THE PERIODIC TABLE LOOK LIKE?
I GROUP/FAMILY – vertical columns
- have similar chemical properties
Group 1A – Alkali Metals
(soft, malleable; lustrous, good conductors,
MOST REACTIVE family of metals)
Group 2A – Alkaline Earth
(higher densities and melting points than
alkali metals; not as reactive as alkali)
Group 7A – Halogens
( MOST REACTIVE Non-Metals; do not
occur free in nature; commonly found
in sea water, minerals, & living tissues)
Group 8A – Noble gases
(VERY INACTIVE elements, used in
balloons, scuba diving tanks, light bulbs)
II PERIODS – horizontal row