Answers

2015-10-21T13:45:55+08:00


the development of the Periodic table could be traced back in 1817 to the work of Johann Dobereiner, a German chemist.


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2015-10-27T18:14:20+08:00
Dmitri Mendeleevis generally credited with the publication, in 1869, of the first widely recognized periodic table. He developed his table to illustrate periodic trends in the properties of the then-known elements. Mendeleev also predicted some properties of then-unknown elementsthat would be expected to fill gaps in this table. Most of his predictions were proved correct when the elements in question were subsequently discovered. Mendeleev's periodic table has since been expanded and refined with the discovery or synthesis of further new elements and the development of new theoretical models to explain chemical behavior.
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