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March 29, 2008
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Free Essay, Research Papers, Term Papers |
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Periodic Table
First noticed by Greek people in about 400BC. They used the words
“element”, and “atom” to describe the differences and smallest parts of
matter. Those ideas lasted for 2000 years. Elements were Earth, Fire, Air,
and Water that explained “world stuff” easily came and went.
In the 1600’s Boyle, an experimenter, influenced by Democritus,
Gassendi, and Descartes lent important weight to the atomic theory of
matter. In the 1700’s Lavoisier divided the elements into four classes.
John Dalton suggested that the mass of an atom is the important property.
“The chemical elements are composed of... indivisible particles of
matter, called atoms... atoms of the same element are identical in all
respects, particularly weight.”
n the 1800’s Doereiner said that some elements had a relative atomic
mass, and DeChancourtois made a table of elements to show the periodic
reoccurrence of properties. In the 1860’s Newland made a table of
elements giving them a serial number in order of their atomic weighs
starting with Hydrogen.
Meyer and Mendeleyev made periodic tables independently. Meyer
made it more periodicity of physical properties, and Mendeleyev made it
more on the chemical properties. Mendeleyev published his periodic table
& law in 1869. Periodic tables have always been related to how scientists
thought about the shape and structure of the atom. Later, the table was
reordered by Mosely according to atomic numbers(nuclear charge) instead
of weight.
Harry D. Hubbard, of the United States National Bureau of
Standards, modernized Mendeleyev’s periodic table. It got published in
1924. It was called the “Periodic Chart of the Atoms.”
In the 1930’s the heaviest elements were being put into the
periodis table. The Alexander Arrangement of the Elements, a
three-dimensional periodic chart designed and patented by Roy Alexander
and introduced in 1994, retains the separate Lenthanide and Actinide
series, but integrated them at the same time, made possible by using all
three dimensions.
The Periodic Table is an arrangement of the chemical elements.
It’s also an important reference for chemists and is the basis of chemical
classification throughout the world.
Bibliography
Barlow, John Perry. The Elements
Mar-Apr. 1995
Word Count: 341
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