रेडियम
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88Ra
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रुप
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silvery white metallic
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साधारण गुण
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नां, चिं, ल्या
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रेडियम, Ra, 88
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उच्चारण
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/ˈreɪdiəm/ RAY-dee-əm
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धातुया वर्ग
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alkaline earth metal
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ग्रुप, पिरियद, ब्लक
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2, 7, s
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Standard atomic weight
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(226)
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Electron configuration
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[Rn] 7s2 2, 8, 18, 32, 18, 8, 2
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History
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Discovery
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पियरे क्युरी व मेरी क्युरी (1898)
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First isolation
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मेरी क्युरी (1902)
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Physical properties
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Phase
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solid
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Density (near r.t.)
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5.5 g·cm−3 |
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Melting point
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973 K, 700 °C, 1292 °F
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Boiling point
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2010 K, 1737 °C, 3158.6 °F
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Heat of fusion
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8.5 kJ·mol−1
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Heat of vaporization
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113 kJ·mol−1 |
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Vapor pressure
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P (Pa)
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1
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10
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100
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1 k
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10 k
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100 k
| at T (K)
|
819
|
906
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1037
|
1209
|
1446
|
1799
|
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Atomic properties
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Oxidation states
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2 (strongly basic oxide)
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Electronegativity
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0.9 (Pauling scale)
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Ionization energies
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1st: 509.3 kJ·mol−1 |
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2nd: 979.0 kJ·mol−1 |
Covalent radius
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221±2 pm
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Van der Waals radius
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283 pm
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Miscellanea
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Crystal structure
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body-centered cubic
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Magnetic ordering
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nonmagnetic
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Electrical resistivity
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(20 °C) 1 µΩ·m
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Thermal conductivity
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18.6 W·m−1·K−1 |
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CAS registry number
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7440-14-4
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Most stable isotopes
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· r
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