Wednesday, July 24, 2013

Periodic table

IMG 2263 Fire at Dayne's Place

http://www.chemicalelements.com/ 

[Periodic Table of the Elements]

FACTS ON GOLD FOR EXAMPLE:
Date of Discovery: circa 3000 BC
Discoverer: Unknown
Name Origin: From the Old English word geolo (yellow)
Symbol Origin: From the Latin word aurum (gold)
Uses: electronics, jewelry, coins
Obtained From: crust of the earth, copper ores


A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Elements are divided into metals, metalloids, and non-metals. Familiar examples of elements include carbon, oxygen (non-metals), silicon, arsenic (metalloids), aluminium, iron, copper, gold, mercury, and lead (metals).

The lightest chemical elements, including hydrogen, helium (and smaller amounts of lithium, beryllium and boron), are thought to have been produced by various cosmic processes during the Big Bang and cosmic-ray spallation.

Production of heavier elements, from carbon to the very heaviest elements, proceeded by stellar nucleosynthesis, and these were made available for later solar system and planetary formation by planetary nebulae and supernovae, which blast these elements into space.

 The high abundance of oxygen, silicon, and iron on Earth reflects their common production in such stars, after the lighter gaseous elements and their compounds have been subtracted. While most elements are generally viewed as stable, a small amount of natural transformation of one element to another also occurs at the present time through decay of radioactive elements as well as other natural nuclear processes.

The history of the discovery and use of the elements began with primitive human societies that found native elements like copper and gold and extracted (smelted) iron and a few other metals from their ores. Alchemists and chemists subsequently identified many more, with nearly all of the naturally-occurring elements becoming known by 1900.

The properties of the chemical elements are often summarized using the periodic table that organizes the elements by increasing atomic number into rows ("periods") in which the columns ("groups") share recurring ("periodic") physical and chemical properties. Save for short-half-life radioactive elements, all of the elements are available industrially, most of them to high degrees of purity.

Hydrogen
and helium are by far the most abundant elements in the universe. However, iron is the most abundant element (by mass) making up the Earth, and oxygen is the most common element in Earth's crust. Although all known chemical matter is composed of these elements, chemical matter itself is hypothesized to constitute only about 15% of the matter in the universe. The remainder is believed to be dark matter, a mysterious substance that is not composed of chemical elements, since it lacks protons, neutrons or electrons. From Wiki
 Dark Matter:

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