The periodic table's name comes from the fact that it arranges the elements into repeating sets, otherwise known as "periods." These periods are defined by the covalence of an element, the number of electrons it has in i... More »

Silver is a naturally occurring element on the periodic table and can be found in natural deposits throughout the world. As such, it was discovered, but not invented, by people. More »

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The chemical symbol "Rb" stands for the element rubidium. A standard periodic table of elements lists the atomic number of rubidium, 37, and the standard atomic weight of rubidium, 85.46 atomic mass units. More »

The periodic table was built to show the relationships among the various elements. The periodic table was constructed in 1869 by Dmitri Mendeleev. More »

Some elements on the periodic table are oxygen, helium, arsenic and fluorine. Oxygen is an odorless, tasteless and colorless gas at room temperature, but is bright blue as a liquid. Oxygen is a very reactive element and ... More »

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The periodic table was invented by chemist Dmitri Mendeleev to organize and compare elements and understand their relations with each other. Mendeleev created the periodic table between 1868 and 1870 while writing his bo... More »

The horizontal rows on the periodic table of the elements are called periods. Every element in a period has the same number of atomic orbitals. For instance, hydrogen and helium are in the first period, so they both have... More »