మూస:రేడియం మూలకము

Radium, 00Ra
Radium
Pronunciation/ˈrdiəm/ (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 Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
Ba

Ra

(Ubn)
franciumradiumactinium
Groupమూస:Infobox element/symbol-to-group/format
Periodperiod 7
Block  s-block
Electron configuration[Rn] 7s2
Electrons per shell2, 8, 18, 32, 18, 8, 2
Physical properties
Phase at STPsolid
Melting point1233 K ​(960 °C, ​1760 °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 Curie and Marie Curie (1898)
First isolationMarie Curie (1910)
Isotopes of radium
Template:infobox radium isotopes does not exist
 Category: Radium
| references

References