Radium

  • radium, 88ra
    radium226.jpg
    radium
    pronunciationm/ (ray-dee-əm)
    appearancesilvery white metallic
    mass number[226]
    radium in the periodic table
    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 iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
    rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver 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 gold mercury (element) thallium lead 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 nihonium flerovium moscovium livermorium tennessine oganesson
    ba

    ra

    (ubn)
    franciumradiumactinium
    atomic number (z)88
    groupgroup 2 (alkaline earth metals)
    periodperiod 7
    blocks-block
    element category  alkaline earth metal
    electron configuration[rn] 7s2
    electrons per shell2, 8, 18, 32, 18, 8, 2
    physical properties
    phase at stpsolid
    melting point973 k ​(700 °c, ​1292 °f) (disputed)
    boiling point2010 k ​(1737 °c, ​3159 °f)
    density (near r.t.)5.5 g/cm3
    heat of fusion8.5 kj/mol
    heat of vaporization113 kj/mol
    vapor pressure
    p (pa) 1 10 100 1 k 10 k 100 k
    at t (k) 819 906 1037 1209 1446 1799
    atomic properties
    oxidation states+2 (expected to have a strongly basic oxide)
    electronegativitypauling scale: 0.9
    ionization energies
    • 1st: 509.3 kj/mol
    • 2nd: 979.0 kj/mol
    covalent radius221±2 pm
    van der waals radius283 pm
    color lines in a spectral range
    spectral lines of radium
    other properties
    natural occurrencefrom decay
    crystal structurebody-centered cubic (bcc)
    body-centered cubic crystal structure for radium
    thermal conductivity18.6 w/(m·k)
    electrical resistivity1 µΩ·m (at 20 °c)
    magnetic orderingnonmagnetic
    cas number7440-14-4
    history
    discoverypierre and marie curie (1898)
    first isolationmarie curie (1910)
    main isotopes of radium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    223ra trace 11.43 d α 219rn
    224ra trace 3.6319 d α 220rn
    225ra trace 14.9 d β 225ac
    226ra trace 1600 y α 222rn
    228ra trace 5.75 y β 228ac
    category category: radium
    | references

    radium is a chemical element with the symbol ra and atomic number 88. it is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (ra3n2). all isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1600 years and decays into radon gas (specifically the isotope radon-222). when radium decays, ionizing radiation is a product, which can excite fluorescent chemicals and cause radioluminescence.

    radium, in the form of radium chloride, was discovered by marie and pierre curie in 1898. they extracted the radium compound from uraninite and published the discovery at the french academy of sciences five days later. radium was isolated in its metallic state by marie curie and andré-louis debierne through the electrolysis of radium chloride in 1911.[1]

    in nature, radium is found in uranium and (to a lesser extent) thorium ores in trace amounts as small as a seventh of a gram per ton of uraninite. radium is not necessary for living organisms, and adverse health effects are likely when it is incorporated into biochemical processes because of its radioactivity and chemical reactivity. currently, other than its use in nuclear medicine, radium has no commercial applications; formerly, it was used as a radioactive source for radioluminescent devices and also in radioactive quackery for its supposed curative powers. today, these former applications are no longer in vogue because radium's toxicity has become known, and less dangerous isotopes are used instead in radioluminescent devices.

  • bulk properties
  • isotopes
  • chemistry
  • occurrence
  • history
  • production
  • modern applications
  • hazards
  • see also
  • notes
  • references
  • bibliography
  • further reading
  • external links

Radium, 88Ra
Radium226.jpg
Radium
Pronunciationm/ (RAY-dee-əm)
Appearancesilvery white metallic
Mass number[226]
Radium in the periodic table
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 Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver 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 Gold Mercury (element) Thallium Lead 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 Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Ba

Ra

(Ubn)
franciumradiumactinium
Atomic number (Z)88
Groupgroup 2 (alkaline earth metals)
Periodperiod 7
Blocks-block
Element category  Alkaline earth metal
Electron configuration[Rn] 7s2
Electrons per shell2, 8, 18, 32, 18, 8, 2
Physical properties
Phase at STPsolid
Melting point973 K ​(700 °C, ​1292 °F) (disputed)
Boiling point2010 K ​(1737 °C, ​3159 °F)
Density (near r.t.)5.5 g/cm3
Heat of fusion8.5 kJ/mol
Heat of vaporization113 kJ/mol
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 819 906 1037 1209 1446 1799
Atomic properties
Oxidation states+2 (expected to have a strongly basic oxide)
ElectronegativityPauling scale: 0.9
Ionization energies
  • 1st: 509.3 kJ/mol
  • 2nd: 979.0 kJ/mol
Covalent radius221±2 pm
Van der Waals radius283 pm
Color lines in a spectral range
Spectral lines of radium
Other properties
Natural occurrencefrom decay
Crystal structurebody-centered cubic (bcc)
Body-centered cubic crystal structure for radium
Thermal conductivity18.6 W/(m·K)
Electrical resistivity1 µΩ·m (at 20 °C)
Magnetic orderingnonmagnetic
CAS Number7440-14-4
History
DiscoveryPierre and Marie Curie (1898)
First isolationMarie Curie (1910)
Main isotopes of radium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
223Ra trace 11.43 d α 219Rn
224Ra trace 3.6319 d α 220Rn
225Ra trace 14.9 d β 225Ac
226Ra trace 1600 y α 222Rn
228Ra trace 5.75 y β 228Ac
Category Category: Radium
| references

Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (Ra3N2). All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1600 years and decays into radon gas (specifically the isotope radon-222). When radium decays, ionizing radiation is a product, which can excite fluorescent chemicals and cause radioluminescence.

Radium, in the form of radium chloride, was discovered by Marie and Pierre Curie in 1898. They extracted the radium compound from uraninite and published the discovery at the French Academy of Sciences five days later. Radium was isolated in its metallic state by Marie Curie and André-Louis Debierne through the electrolysis of radium chloride in 1911.[1]

In nature, radium is found in uranium and (to a lesser extent) thorium ores in trace amounts as small as a seventh of a gram per ton of uraninite. Radium is not necessary for living organisms, and adverse health effects are likely when it is incorporated into biochemical processes because of its radioactivity and chemical reactivity. Currently, other than its use in nuclear medicine, radium has no commercial applications; formerly, it was used as a radioactive source for radioluminescent devices and also in radioactive quackery for its supposed curative powers. Today, these former applications are no longer in vogue because radium's toxicity has become known, and less dangerous isotopes are used instead in radioluminescent devices.