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Podcast: 4. Chemistry and Physics
Episode:

Periodic Table
Category: Science & Medicine
Duration: 00:00:57
Publish Date: 2011-07-13 19:29:09
Description: Transcript: In the early 1800s only 30 elements were known, insufficient to see any pattern in their behavior. Around this time the battery was invented which led to the isolation, by chemical means, of several dozen additional elements. The Swedish chemist Berzelius invented the modern notation of chemistry, H20 and CO2 for example, where a compound is represented by the relative number of atoms of different elements in it. In 1869 the Russian chemist Mendeleev took the existing set of elements and arranged them by weight and chemical properties into the periodic table. The modern form of the periodic table has 90 stable elements and several dozen elements that can be created fleetingly only in the laboratory. These are among the most heavy elements.
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