Uranium

Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons.

Characteristics

Uranium is weakly radioactive because all isotopes of uranium are unstable; the two naturally occurring isotopes with significant half-lives are Uranium-235 and Uranium-238. When refined, uranium is a silvery white, weakly radioactive metal, which is slightly softer than steel, and is malleable, ductile, and slightly paramagnetic.

Isotopes

Uranium has the highest atomic weight of the naturally occurring elements. Its two principal isotopes are Uranium-235 and Uranium-238 with 143 and 146 neutrons respectively. Uranium-235 is the only naturally occurring fissile isotope. It makes up approximately 0.72% of natural uranium.

Uses

The primary use of uranium in the civilian sector is to fuel nuclear power plants. One kilogram of uranium-235 can theoretically produce about 20 terajoules of energy (2 million times more than natural gas). Uranium is also used in the military sector for high-density penetrators.

Health effects

Exposure to uranium can result in both chemical and radiological toxicity. The use of Depleted uranium in munitions is controversial because of questions about potential long-term health effects.

See also

• Nuclear fission
• Nuclear power
• Nuclear weapon
• Depleted uranium
• Uranium mining
• Uranium market

Periodic table

Group	1	2		3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
	Hydrogen & alkali metals	Alkaline earth metals												Triels	Tetrels	Pnicto­gens	Chal­co­gens	Halo­gens	Noble gases
Period 1	Hydro­gen1H​																		He­lium2He​
2	Lith­ium3Li​	Beryl­lium4Be​												Boron5B​	Carbon6C​	Nitro­gen7N​	Oxy­gen8O​	Fluor­ine9F​	Neon10Ne​
3	So­dium11Na​	Magne­sium12Mg​												Alumin­ium13Al​	Sili­con14Si​	Phos­phorus15P​	Sulfur16S​	Chlor­ine17Cl​	Argon18Ar​
4	Potas­sium19K​	Cal­cium20Ca​		Scan­dium21Sc​	Tita­nium22Ti​	Vana­dium23V​	Chrom­ium24Cr​	Manga­nese25Mn​	Iron26Fe​	Cobalt27Co​	Nickel28Ni​	Copper29Cu​	Zinc30Zn​	Gallium31Ga​	Germa­nium32Ge​	Arsenic33As​	Sele­nium34Se​	Bromine35Br​	Kryp­ton36Kr​
5	Rubid­ium37Rb​	Stront­ium38Sr​		Yttrium39Y​	Zirco­nium40Zr​	Nio­bium41Nb​	Molyb­denum42Mo​	Tech­netium43Tc​[97]	Ruthe­nium44Ru​	Rho­dium45Rh​	Pallad­ium46Pd​	Silver47Ag​	Cad­mium48Cd​	Indium49In​	Tin50Sn​	Anti­mony51Sb​	Tellur­ium52Te​	Iodine53I​	Xenon54Xe​
6	Cae­sium55Cs​	Ba­rium56Ba​		Lute­tium71Lu​	Haf­nium72Hf​	Tanta­lum73Ta​	Tung­sten74W​	Rhe­nium75Re​	Os­mium76Os​	Iridium77Ir​	Plat­inum78Pt​	Gold79Au​	Mer­cury80Hg​	Thallium81Tl​	Lead82Pb​	Bis­muth83Bi​	Polo­nium84Po​[209]	Asta­tine85At​[210]	Radon86Rn​[222]
7	Fran­cium87Fr​[223]	Ra­dium88Ra​[226]		Lawren­cium103Lr​[266]	Ruther­fordium104Rf​[267]	Dub­nium105Db​[268]	Sea­borgium106Sg​[269]	Bohr­ium107Bh​[270]	Has­sium108Hs​[269]	Meit­nerium109Mt​[278]	Darm­stadtium110Ds​[281]	Roent­genium111Rg​[282]	Coper­nicium112Cn​[285]	Nihon­ium113Nh​[286]	Flerov­ium114Fl​[289]	Moscov­ium115Mc​[290]	Liver­morium116Lv​[293]	Tenness­ine117Ts​[294]	Oga­nesson118Og​[294]
				Lan­thanum57La​	Cerium58Ce​	Praseo­dymium59Pr​	Neo­dymium60Nd​	Prome­thium61Pm​[145]	Sama­rium62Sm​	Europ­ium63Eu​	Gadolin­ium64Gd​	Ter­bium65Tb​	Dyspro­sium66Dy​	Hol­mium67Ho​	Erbium68Er​	Thulium69Tm​	Ytter­bium70Yb​
				Actin­ium89Ac​[227]	Thor­ium90Th​	Protac­tinium91Pa​	Ura­nium92U​	Neptu­nium93Np​[237]	Pluto­nium94Pu​[244]	Ameri­cium95Am​[243]	Curium96Cm​[247]	Berkel­ium97Bk​[247]	Califor­nium98Cf​[251]	Einstei­nium99Es​[252]	Fer­mium100Fm​[257]	Mende­levium101Md​[258]	Nobel­ium102No​[259]

Primordial  From decay  Synthetic Border shows natural occurrence of the element

Standard atomic weight A_{r, std}(E)

• Ca:  — Abridged value (uncertainty omitted here)
• Po: [209] — mass number of the most stable isotope

s-block

f-block

d-block

p-block

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