Radium, 88Ra |
General properties |
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Pronunciation | Template:Infobox element/pronunciation |
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Appearance | silvery white metallic |
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Standard atomic weight (Ar, standard) | Template:Infobox element/standard atomic weight |
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Mass number | Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope) |
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Radium in the periodic table |
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Template:Infobox element/periodic table |
Atomic number (Z) | 88 |
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Group | Template:Infobox element/group |
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Period | period 7 |
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Block | s-block |
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Element category | Template:Infobox element/category format |
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Electron configuration | [Rn] 7s2 |
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Electrons per shell | 2, 8, 18, 32, 18, 8, 2 |
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Physical properties |
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Phase at STP | solid |
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Melting point | 973 K (700 °C, 1292 °F) (disputed) |
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Boiling point | 2010 K (1737 °C, 3159 °F) |
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Density (near r.t.) | 5.5 g/cm3 |
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Heat of fusion | 8.5 kJ/mol |
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[[Enthalpy of vaporization|Heat of Template:Engvar]] | 113 kJ/mol |
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[[Vapor pressure|Template:Engvar pressure]] |
Atomic properties |
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Oxidation states | Template:Infobox element/symbol-to-oxidation-state |
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Electronegativity | Pauling scale: 0.9 |
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[[Ionization energy|Template:Engvar energies]] | - 1st: 509.3 kJ/mol
- 2nd: 979.0 kJ/mol
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Covalent radius | 221±2 pm |
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Van der Waals radius | 283 pm |
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Template:Infobox element/spectral lines |
Other properties |
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Crystal structure | Template:Infobox element/crystal structure |
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Thermal conductivity | 18.6 W/(m·K) |
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Electrical resistivity | 1 µΩ·m (at 20 °C) |
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Magnetic ordering | nonmagnetic |
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CAS Number | 7440-14-4 |
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History |
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Discovery | Pierre and Marie Curie (1898) |
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First isolation | Marie Curie (1910) |
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Main isotopes of radium |
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Template:Infobox element/isotopes table |
| references |
Template:Infobox element/element navigation
Template:Template reference list
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