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Atomic Number: 3
3
Li
Lithium
6.941
Atomic Weight: 6.941
Melting Point: 453.65 K (180.50°C or 356.90°F)
Boiling Point: 1615 K (1342°C or 2448°F)
Density: 0.534 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 2 Group Number: 1 Group Name: Alkali Metal
What's in a name? From the Greek word for stone, lithos.
Say what? Lithium is pronounced as LITH-i-em.
History and Uses:
Lithium was discovered in the mineral petalite (LiAl(Si2O5)2) by Johann
August Arfvedson in 1817. It was first isolated by William Thomas
Brande and Sir Humphrey Davy through the electrolysis of lithium oxide
(Li2O). Today, larger amounts of the metal are obtained through the
electrolysis of lithium chloride (LiCl). Lithium is not found free in nature
and makes up only 0.0007% of the earth's crust.
Many uses have been found for lithium and its compounds. Lithium has
the highest specific heat of any solid element and is used in heat transfer
applications. It is used to make special glasses and ceramics, including
the Mount Palomar telescope's 200 inch mirror. Lithium is the lightest
known metal and can be alloyed with aluminium, copper, manganese,
and cadmium to make strong, lightweight metals for aircraft. Lithium
hydroxide (LiOH) is used to remove carbon dioxide from the atmosphere
of spacecraft. Lithium stearate (LiC18H35O2) is used as a general purpose
and high temperature lubricant. Lithium carbonate (Li2CO3) is used as a
drug to treat manic depression disorder.
Lithium reacts with water, but not as violently as sodium.
Estimated Crustal Abundance: 2.0×101 milligrams per kilogram
Estimated Oceanic Abundance: 1.8×10-1 milligrams per liter
Number of Stable Isotopes: 2 (View all isotope data)
Ionization Energy: 5.392 eV
Oxidation State: +1
Atomic Number: 12
12
Mg
Magnesium
24.3050
Atomic Weight: 24.3050
Melting Point: 923 K (650°C or 1202°F)
Boiling Point: 1363 K (1090°C or 1994°F)
Density: 1.74 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 3 Group Number: 2 Group Name: Alkaline Earth Metal
What's in a name? For Magnesia, a district in the region of Thessaly, Greece.
Say what? Magnesium is pronounced as mag-NEE-zhi-em.
History and Uses:
Although it is the eighth most abundant element in the universe and the
seventh most abundant element in the earth's crust, magnesium is never
found free in nature. Magnesium was first isolated by Sir Humphry
Davy, an English chemist, through the electrolysis of a mixture of
magnesium oxide (MgO) and mercuric oxide (HgO) in 1808. Today,
magnesium can be extracted from the minerals dolomite (CaCO3·MgCO3)
and carnallite (KCl·MgCl2·6H2O), but is most often obtained from
seawater. Every cubic kilometer of seawater contains about 1.3 billion
kilograms of magnesium (12 billion pounds per cubic mile).
Magnesium burns with a brilliant white light and is used in
pyrotechnics, flares and photographic flashbulbs. Magnesium is the
lightest metal that can be used to build things, although its use as a
structural material is limited since it burns at relatively low temperatures.
Magnesium is frequently alloyed with aluminum, which makes
aluminum easier to roll, extrude and weld. Magnesium-aluminum alloys
are used where strong, lightweight materials are required, such as in
airplanes, missiles and rockets. Cameras, horseshoes, baseball catchers'
masks and snowshoes are other items that are made from magnesium
alloys.
Magnesium oxide (MgO), also known as magnesia, is the second most
abundant compound in the earth's crust. Magnesium oxide is used in
some antacids, in making crucibles and insulating materials, in refining
some metals from their ores and in some types of cements. When
combined with water (H2O), magnesia forms magnesium hydroxide
(Mg(OH)2), better known as milk of magnesia, which is commonly used
as an antacid and as a laxative.
Hydrated magnesium sulphate (MgSO4·7H2O), better known as Epsom
salt, was discovered in 1618 by a farmer in Epsom, England, when his
cows refused to drink the water from a certain mineral well. He tasted the
water and found that it tasted very bitter. He also noticed that it helped
heal scratches and rashes on his skin. Epsom salt is still used today to
treat minor skin abrasions.
Other magnesium compounds include magnesium carbonate (MgCO3)
and magnesium fluoride (MgF2). Magnesium carbonate is used to make
some types of paints and inks and is added to table salt to prevent caking.
A thin film of magnesium fluoride is applied to optical lenses to help
reduce glare and reflections.
Estimated Crustal Abundance: 2.33×104 milligrams per kilogram
Estimated Oceanic Abundance: 1.29×103 milligrams per liter
Number of Stable Isotopes: 3 (View all isotope data)
Ionization Energy: 7.646 eV
Oxidation State: +2
Electron Shell Configuration: 1s2
2s2 2p6
3s2