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Radium Ra (Element 88) of Periodic Table

Radium Ra (Element 88) of Periodic Table

88 Ra (Radium)

Appearance:  Soft, shiny, Silvery white metallic

Mass number:  226

Atomic weight:  226.0254 g/mol

Atomic number(Z):  88

Electrons:  88

Protons:  88

Neutrons:  138

Group:  2

Period:  7

Block:  s

Element category:  Alkaline earth metal

Electrons per shell:  K2, L8, 18, M32, N18, O8, P2

Electron configuration:  1s22s22p63s23p63d104s24p64d105s25p64f145d106s26p67s2

Phase:  Solid

Melting point:  973 K (700 oC)

Boiling point:  2010 K (1737 oC)

Density:  5.5 g/cm3

Molar volume: 0.000045 m3/mol

Thermal conductivity:  19 W/m∙K

Half Life: 5×1010

Lifetime:  7.3×1010

Decay mode: α decay

Neutron cross section (Barns): 20

Heat of fusion:  8.5 kJ/mol

Heat of vaporization:  113 kJ/mol

Oxidation states:  2

Ion charge:  Ra2+

The ionization potential of an atom:  5.4

Electronegativity:  0.9

Valence: 2

Ionization energies:  1st: 509.3 kJ/mol 2nd: 979.0 kJ/mol

Atomic radius:  215 pm

Covalent radius:  221±2 pm

Vander Waals radius:  283 pm

Crystal structure:  Body-centered cubic

Thermal conductivity:  18.6 W/(m∙K)

Electrical resistivity:  1 μΩ∙m

Electrical conductivity:  1000000 s/m

Electrical type: Conductor

Magnetic ordering:  Nonmagnetic

CAS Number:  7440-14-4

Discovery:  Pierre and Marie Curie (1898)

1st isolation:  Marie Curie (1910)

Isotopes:  223Ra 224Ra 225Ra 226Ra 228Ra

Uses:   It is used in luminous paints, Radium-223 is used to treat prostate cancer

Biological role:  It is toxic due to its highly radioactivity

Natural abundance:  It is Present in all Uranium ores. 1×10-10%(In Earth’s Crust), 1×10-15%(In Oceans), 1×10-13%(In Humans)


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