Radium

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Categories: Periodic Element

RadiumType: Periodic Element
Periodic Element: (Ra)
RDA: 0.1 micrograms of ingested radium. (maximum daily dose, 1944)
Importance- to Body:
Toxic
Distribution- In Body:
When ingested, 80% of the ingested radium leaves the body through the feces, while the other 20% goes into the bloodstream, mostly accumulating in the bones.
Excess Effects:
Radium-dermatitis, Dermatitis, Cancer, Cell Death, Cell Mutation, Other Disorders
Deficiency Effects:
None listed
Sources Food:
None listed
Sources Environmental/Geographic:
In nature, radium is found in tiny quantities in the uranium ore uraninite and various other uranium minerals, and in even tinier quantities in thorium minerals. One ton of pitchblende typically yields about one seventh of a gram of radium. One kilogram of the Earth’s crust contains about 900 picograms of radium, and one liter of sea water contains about 89 femtograms of radium.
Supplemental information:

Related Articles:
  • Supplemental: Radon
    Epidemiological studies have shown a clear link between breathing high concentrations of radon and incidence of lung cancer. Radon is a contaminant that affects indoor air quality worldwide.
Radium (Wikipedia)
This article is about the chemical element. For other uses, see Radium (disambiguation).
Radium,  88Ra
Radium226.jpg
General properties
Pronunciation /ˈreɪdiəm/ ​(RAY-dee-əm)
Appearance silvery white metallic
Mass number 226 (most stable isotope)
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)
francium ← radium → actinium
Atomic number (Z) 88
Group group 2 (alkaline earth metals)
Period period 7
Element category   alkaline earth metal
Block s-block
Electron configuration [Rn] 7s2
Electrons per shell
 2, 8, 18, 32, 18, 8, 2
Physical properties
Phase at STP solid
Melting point 973 K ​(700 °C, ​1292 °F) (disputed)
Boiling point 2010 K ​(1737 °C, ​3159 °F)
Density (near r.t.) 5.5 g/cm3
Heat of fusion 8.5 kJ/mol
Heat of vaporization 113 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)
Electronegativity Pauling scale: 0.9
Ionization energies
  • 1st: 509.3 kJ/mol
  • 2nd: 979.0 kJ/mol
Covalent radius 221±2 pm
Van der Waals radius 283 pm
Color lines in a spectral range
Miscellanea
Crystal structure ​body-centered cubic (bcc)
Body-centered cubic crystal structure for radium
Thermal conductivity 18.6 W/(m·K)
Electrical resistivity 1 µΩ·m (at 20 °C)
Magnetic ordering nonmagnetic
CAS Number 7440-14-4
History
Discovery Pierre and Marie Curie (1898)
First isolation Marie 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
| references | in Wikidata

Radium is a chemical element with 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.

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 since become known, and less dangerous isotopes are used instead in radioluminescent devices.

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