Lithium, symbolized as Li¸ is the third element on the periodic table of elements, after hydrogen and helium. Accordingly, its atomic number is 3 and is composed of three protons and four neutrons.
Properties of Lithium
Lithium appears as a soft, silvery rock. Its surface turns gray after a minute or so’s exposure to oxygen. It is categorized as an alkali metal. It is the lightest of all metals and the only alkali metal that does not react violently when exposed to oxygen. Like other alkali metals, lithium is soft, malleable, and a good conductor of heat and electricity. Also like alkali metals, lithium is a very reactive metal that does not occur freely in nature. Lithium normally occurs in an isotope form known as lithium-7.
Lithium's Abundance in the Universe
Only a tiny amount of lithium is found distributed through the Universe and even less is detected in the Sun. Refer to any chart of the main elements' abundance in the Universe and it is apparent that lithium is unusually rare.
There are several reasons for this. According to the article Lithium Chemisty of the Early Universe by Stancel et al (published in 1996 in the Astrophysical Journal), for the few minutes after the Universe first theoretically exploded out the Big Bang only the first three elements, deuterium (an isotope of hydrogen), helium and lithium, were created out of the pool of subatomic particles. Mainly deuterium and helium were created, with trace amounts of lithium in the mix. This gave lithium a head start in conditions ideal for creation over Boron and Beryllium, the two rare elements that follow it in the periodic table. However, due to lithium's unstable nature, it reacts quickly with other elements and remains a rare find.
Spallation
Lithium began in low in numbers in Universe due to its instability, and remains so because new lithium is rarely produced. In the vacuum of space, lithium is also usually newly created by an uncommon process known as spallation. Spallation is known to be the main process by which lighter elements are currently formed in the Universe. Spallation occurs when heavy elements are split into lighter ones by cosmic rays. Because cosmic rays are unusual in the vast emptiness of space, lithium rarely gets the chance to be produced. Even, when spallation is able to occur, it usually results in slightly heavier elements, such as beryllium and boron, according to Maia Weinstock's article Astronomers Discover Origin of Light Elements on Space.com.
Lithium: Rare and Unique
Lithium’s unique properties as the lightest metal contribute to its widely varying uses in geological and biological spheres, and but composition and physical properties make this simple element hard to come by in the Universe.
Sources
Lithium Chemisty of the Early Universe by Stancil, P. C., Lepp, S., Dalgarno, A., & Kirby, K. published in the Astrophysical Journal, 1996
It's Elemental - Lithium by Steven Gagnon of Jefferson Labs. Published March 11, 2005 and retrieved from chemicalelements.com
Astronomers Discover Origin of Light Elements by Maia Weinstock from Space.com. Published June 6, 2004.
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