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But first, check out the LIMITED TIME, SCHOOL ONLY,
BIG SALE OF CLASSROOM SETS OF 3-D PERIODIC TABLES. |
Things are different from each other, and each can be reduced to very small parts of itself. - Ancient knowledge
This was noticed early by people, and Greek thinkers, about 400 BC, used the words "element', and `atom' to describe the differences and smallest parts of matter. These ideas survived for 2000 years while concepts such as `Elements' of Earth, Fire, Air, and Water to explain `world stuff' came and went. "The chemical elements are composed of... indivisible particles of matter, called atoms... atoms of the same element are identical in all respects, particularly weight."   - Dalton
In the early 1800's Dobereiner noted that similar elements often had relative atomic masses, and DeChancourtois made a cylindrical table of elements to display the periodic reoccurrence of properties.
Both Meyer and Mendeleyev constructed periodic tables independently that are credited as being the basis of the modern table. Meyer was more impressed by the periodicity of physical properties, while Mendeleyev was more interested in the chemical properties. Dimitri Mendeleyev "...if all the elements be arranged in order of their atomic weights a periodic repetition of properties is obtained." - Mendeleyev
Mendeleyev published his periodic table & law in 1869 and forecast the properties of missing elements, and chemists began to appreciate it when the discovery of elements predicted by the table took place. Periodic tables have always been related to the way scientists thought about the shape and structure of the atom, and has changed accordingly.
The Periodic Law revealed important analogies among the 94 naturally occurring elements, and stimulated renewed interest in Inorganic Chemistry in the nineteenth century which has carried into the present with the creation of artificially produced, short lived elements of `atom smashers' and supercolliders of high energy physics. Dr.Glenn T.Seaborg in 1968
Into the 1930s the heaviest elements were being put up in the body of the periodic table, and Glenn Seaborg "plucked those out" while working with Fermi in Chicago, naming them the Actinide series, which later permitted proper placement of subsequently 'created' elements - the Transactinides, changing the periodic table yet again. These elements were shown separate from the main body of the table. |
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Reviews of a few Periodic Table Resources for Study and Homework |
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Alexander's Arrangement Gray's Illustrated Scerri's Books Element Cards
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