Magnesium

Magnesium is a chemical element wi seembol Mg an atomic nummer 12. It is a shiny gray solit which bears a close pheesical resemblance tae the ither five elements in the seicont column (Group 2, or alkaline yird metals) o the periodic cairt: thay each hae the same electron confeeguration in thair ooter electron shell producin a seemilar crystal structur.

Magnesium, ₁₂Mg

Magnesium
Pronunciation	/mæɡˈniːziəm/ ​(mag-NEE-zee-əm)
Appearance	shiny gray solit
Standard atomic weight Ar, std(Mg)	[7001243040000000000♠24.304, 7001243070000000000♠24.307] conventional: 7001243050000000000♠24.305
Magnesium in the periodic cairt
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium Be ↑ Mg ↓ Ca sodium ← magnesium → alumeenium
Atomic nummer (Z)	12
Group	group 2 (alkaline yird metals)
Period	period 3
Block	s-block
Element category	Alkaline yird metal
Electron confeeguration	[Ne] 3s2
Electrons per shell	2, 8, 2
Pheesical properties
Phase at STP	solit
Meltin pynt	923 K ​(650 °C, ​1202 °F)
Bylin pynt	1363 K ​(1091 °C, ​1994 °F)
Density (near r.t.)	1.738 g/cm3
when liquid (at m.p.)	1.584 g/cm3
Heat o fusion	8.48 kJ/mol
Heat o vapourisation	128 kJ/mol
Molar heat capacity	24.869 J/(mol·K)
Vapour pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 701 773 861 971 1132 1361
Atomic properties
Oxidation states	+1, +2 strangly basic
Electronegativity	Pauling scale: 1.31
Ionisation energies	1st: 737.7 kJ/mol 2nd: 1450.7 kJ/mol 3rd: 7732.7 kJ/mol (more)
Atomic radius	empirical: 160 pm
Covalent radius	141±7 pm
Van der Waals radius	173 pm
Colour lines in a spectral range Spectral lines o magnesium
Ither properties
Naitural occurrence	primordial
Creestal structur	​hexagonal close-packed (hcp)
Speed o soond thin rod	4940 m/s (at r.t.) (annealed)
Thermal expansion	24.8 µm/(m·K) (at 25 °C)
Thermal conductivity	156 W/(m·K)
Electrical resistivity	43.9 nΩ·m (at 20 °C)
Magnetic orderin	paramagnetic
Magnetic susceptibility	+13.1·10−6 cm3/mol (298 K)
Young's modulus	45 GPa
Shear modulus	17 GPa
Bulk modulus	35.4 GPa
Poisson ratio	0.290
Mohs haurdness	1–2.5
Brinell haurdness	44–260 MPa
CAS Nummer	7439-95-4
History
Namin	after Magnesia, Greece
Diskivery	Joseph Black (1755)
First isolation	Humphry Davy (1808)
Main isotopes o magnesium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 24Mg 79.0% stable 25Mg 10.0% stable 26Mg 11.0% stable

Magnesium is the nint maist abundant element in the universe. It is produced in muckle, agein starns frae the sequential addeetion o three helium nuclei tae a caurbon nucleus. Whan sic starns explode as supernovas, muckle o the magnesium is expelled intae the interstellar medium whaur it mey recycle intae new starn seestems. Magnesium is the aicht maist abundant element in the Yird's crust an the fowerth maist common element in the Yird (efter airn, oxygen an silicon), makkin up 13% o the planet's mass an a muckle fraction o the planet's mantle. It is the third maist abundant element dissolved in seawater, efter sodium an chlorine.

Magnesium occurs naiturally anly in combination wi ither elements, whaur it invariably has a +2 oxidation state. The free element (metal) can be produced artifeecially, an is heichly reactive (tho in the atmosphere, it is suin coatit in a thin layer o oxide that pairtly inhibits reactivity — see passivation). The free metal birns wi a chairactereestic brilliant-white licht. The metal is nou obteened mainly bi electrolysis o magnesium sauts obteened frae brack, an is uised primarily as a component in alumeenium-magnesium alloys, whiles cried magnalium or magnelium. Magnesium is less dense nor alumeenium, an the alloy is prized for its combination o lichtness an strenth.

Magnesium is the eleivent maist abundant element bi mass in the human bouk an is essential tae aw cells an some 300 enzymes. Magnesium ions interact wi polyphosphate compoonds sic as ATP, DNA, an RNA. Hunders o enzymes require magnesium ions tae function. Magnesium compoonds are uised medicinally as common laxatives, antacids (e.g., milk o magnes), an tae stabilise abnormal nerve excitation or bluid veshel spasm in sic condeetions as eclampsia.