Radium

Source of the photo
http://reich-chemistry.wikispaces.com/422-004+N.+sherman+and+N.+swanson+big+timeline+project
Author of the description
Gruiz Katalin

Atomic number

88

Atomic mass

226.0254 g.mol -1

Electronegativity

0.9

Density

5 g.cm-3 at 20°C

Melting point

700 °C

Boiling point

1140 °C

Vanderwaals radius

0.230 nm

Ionic radius

unknown

Isotopes

6

Electronic shell

[ Rn ] 7s2

Energy of first ionisation

509.1 kJ.mol -1

Energy of second ionisation

975 kJ.mol -1

Discovered by Pierre and Marie Curie 1898

 

Radium is silvery, lustrous, soft, intensely radioactive. It readily oxidizes on exposure to air, turning from almost pure white to black. Radium is luminescent, corrodes in water to form radium hydroxide. Although is the heaviest member of the alkaline-earth group it is the most volatile.

Applications

Radium is used in luminous paint (in the form of radium bromide). Radium and beryllium were once used as a portable source of neutrons. Radium is used in medicine to produce radon gas, used for cancer treatment. At the beginning of the 19th century radium was used as additive in products like toothpaste, hair creams and even food items.