Uranium

Uranium is a chemical element wi seembol U an atomic nummer 92. It is a sillery-white metal in the actinide series o the periodic table. A uranium atom haes 92 protons an 92 electrons, o that 6 are valence electrons. Uranium is waikly radioactive acause aw isotopes o uranium are unstable, wi hauf-lives varyin atween 159,200 year an 4.5 billion year lang. The maist common isotopes in naitural uranium are uranium-238 (that haes 146 neutrons an accoonts for ower 99%) an uranium-235 (that haes 143 neutrons). Uranium haes the heichest atomic wecht o the primordially occurrin elements. Its density is aboot 70% heicher than that o leid, an slichtly lawer than that o gowd or tungsten. It occurs naiturally in law concentrations o a few pairts per million in syle, rock an watter, an is commercially extractit frae uranium-beirin minerals sic as uraninite.^[3]

Uranium, ₉₂U

Uranium
Pronunciation	/j[unsupported input]eɪniəm/ ​(yoor-AY-nee-əm)
Appearance	sillery gray metallic; corrodes tae a spallin black oxide coat in air
Standard atomic weight Ar, std(U)	7002238028910000000♠238.02891(3)[1]
Uranium 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 Nd ↑ U ↓ (Uqh) protactinium ← uranium → neptunium
Atomic nummer (Z)	92
Group	group n/a
Period	period 7
Block	f-block
Element category	Actinide
Electron confeeguration	[Rn] 5f3 6d1 7s2
Electrons per shell	2, 8, 18, 32, 21, 9, 2
Pheesical properties
Phase at STP	solid
Meltin pynt	1405.3 K ​(1132.2 °C, ​2070 °F)
Bylin pynt	4404 K ​(4131 °C, ​7468 °F)
Density (near r.t.)	19.1 g/cm3
when liquid (at m.p.)	17.3 g/cm3
Heat o fusion	9.14 kJ/mol
Heat o vapourisation	417.1 kJ/mol
Molar heat capacity	27.665 J/(mol·K)
Vapour pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 2325 2564 2859 3234 3727 4402
Atomic properties
Oxidation states	+1, +2, +3,[2] +4, +5, +6 waikly basic
Electronegativity	Pauling scale: 1.38
Ionisation energies	1st: 597.6 kJ/mol 2nd: 1420 kJ/mol
Atomic radius	empirical: 156 pm
Covalent radius	196±7 pm
Van der Waals radius	186 pm
Colour lines in a spectral range Spectral lines o uranium
Ither properties
Naitural occurrence	primordial
Creestal structur	​orthorhombic
Speed o soond thin rod	3155 m/s (at 20 °C)
Thermal expansion	13.9 µm/(m·K) (at 25 °C)
Thermal conductivity	27.5 W/(m·K)
Electrical resistivity	0.280 µΩ·m (at 0 °C)
Magnetic orderin	paramagnetic
Young's modulus	208 GPa
Shear modulus	111 GPa
Bulk modulus	100 GPa
Poisson ratio	0.23
Vickers haurdness	1960–2500 MPa
Brinell haurdness	2350–3850 MPa
CAS Nummer	7440-61-1
History
Namin	efter planet Uranus, itsel named efter Greek god o the sky Uranus
Diskivery	Martin Heinrich Klaproth (1789)
First isolation	Eugène-Melchior Péligot (1841)
Main isotopes o uranium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 232U syn 68.9 y SF – α 228Th 233U trace 1.592×105 y SF – α 229Th 234U 0.005% 2.455×105 y SF – α 230Th 235U 0.720% 7.04×108 y SF – α 231Th 236U trace 2.342×107 y SF – α 232Th 238U 99.274% 4.468×109 y α 234Th SF – β−β− 238Pu
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In naitur, uranium is foond as uranium-238 (99.2739–99.2752%), uranium-235 (0.7198–0.7202%), an a verra smaw amoont o uranium-234 (0.0050–0.0059%).^[4] Uranium decays slawly bi emittin an alpha pairticle. The hauf-life o uranium-238 is aboot 4.47 billion years an that o uranium-235 is 704 million years,^[5] makkin them uisefu in datin the age o the Yird.

Mony contemporary uises o uranium exploit its unique nuclear properties. Uranium-235 is the anly naiturally occurrin fissile isotope, that maks it widely uised in nuclear pouer plants an nuclear wappens. Houiver, acause o the teenie amoonts foond in naitur, uranium needs tae unnergae enrichment sae that eneuch uranium-235 is present. Uranium-238 is fissionable bi fest neutrons, an is fertile, meanin it can be transmutit tae fissile plutonium-239 in a nuclear reactor. Anither fissile isotope, uranium-233, can be produced frae naitural thorium an is an aa important in nuclear technology. Uranium-238 haes a smaw probability for spontaneous fission or even induced fission wi fest neutrons; uranium-235 an tae a lesser degree uranium-233 hae a muckle heicher fission cross-section for slaw neutrons. In sufficient concentration, thir isotopes mainteen a susteened nuclear cheen reaction. This generates the heat in nuclear pouer reactors, an produces the fissile material for nuclear wappens. Depletit uranium (²³⁸U) is uised in kinetic energy penetrators an airmour platin.^[6] Uranium is uised as a colourant in uranium gless, producin leemon yellae tae green colors. Uranium gless fluoresces green in ultraviolet licht. It wis an aa uised for tintin an shadin in early photografie.

The 1789 diskivery o uranium in the meeneral pitchblende is creditit tae Martin Heinrich Klaproth, that named the new element efter the planet Uranus. Eugène-Melchior Péligot wis the first person tae isolate the metal an its radioactive properties war diskivert in 1896 bi Henri Becquerel. Resairch bi Otto Hahn, Lise Meitner, Enrico Fermi an ithers, sic as J. Robert Oppenheimer stairtin in 1934 led tae its uise as a fuel in the nuclear pouer industry an in Little Boy, the first nuclear wappen uised in war. An ensuin airms race in the Cauld War atween the Unitit States an the Soviet Union produced tens o thoosands o nuclear wappens that uised uranium metal an uranium-derived plutonium-239. The siccarity o thae wappens an thair fissile material follaein the brakup o the Soviet Union in 1991 is an ongaein concern for public heal an saufty.^[7] See Nuclear proliferation.