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56
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57
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87
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88
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89
 
 
 

 

Periodic table

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Radium

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Radium

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Radium

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Ra
Ra
Radium

PERIODIC TABLE OF THE ELEMENTS

RADIUM

ALKALINE EARTH METAL

 

Atomic number:88

Group numbers:2

Period:7

Electronic configuration:[Rn] 7s2

Formal oxidation number:+2

Electronegativities:0.9

Atomic radius / pm:235

Relative atomic mass:[226]

 

Radium was discovered by Marie Sklodowska Curie and Perre Curie (FR) in 1898. The origin of the name comes from the Latin word radius meaning ray. It is a silvery-white radioactive metal that reacts with oxygen and water. It is highly radiotoxic and carcinogen by inhalation, ingestion, or exposure. Radium is found in uranium ores at 1 part per 3 million parts uranium. Used in treating cancer because of the gamma rays it gives off.

PHYSICAL PROPERTIES

Density / g dm-3:5000 (293 K)

Molar volume / cm3mol-1:45.20 (est., 293 K)

Electrical resistivity / μΩcm:100 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:18.6

Melting point / °C:700

Boiling point / °C:1140

Heat of fusion / kJ mol-1:7.15

Heat of vaporization / kJ mol-1:136.7

Heat of atomization / kJ mol-1:159

IONIZATION ENERGIES

First ionization energy / kJ mol-1:509.29

Second ionization energy / kJ mol-1:979.06

Third ionization energy / kJ mol-1:-

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:-

in the oceans / ppm:3E-11

CRYSTALLOGRAPHIC DATA

body-centered cubic

Crystal structure:

body-centered cubic

Unit-cell dimensions / pm:

a=515

Space group:

Im3m

ISOTOPES

IsotopeRelative atomic massMass percent (%)
223Ra223.018497(3)*
225Ra225.023604(3)*
226Ra226.025403(3)*

REDUCTION POTENTIALS

Balanced half-reaction Eo / V
Ra2+ + 2e- = Ra(s)- 2.92

 

87 Francium <=
88 Radium
 => 89 Actinium