88 Ra 226
Radium
Alkaline Earth Metal
Radium (Ra) is a chemical element with atomic number 88, classified as a alkaline earth metal. At room temperature it is a solid. It was discovered in 1898 by Marie and Pierre Curie.
Properties
- Atomic number
- 88
- Atomic mass
- 226 u
- Category
- Alkaline Earth Metal
- Group
- 2
- Period
- 7
- Block
- s-block
- Electron configuration
- [Rn] 7s²
- Phase at STP
- Solid
- Density
- 5.5 g/cm³
- Melting point
- 973 K (699.9 °C)
- Boiling point
- 2010 K (1736.8 °C)
- Electronegativity
- 0.9
- Atomic radius
- 283 pm
- Ionization energy
- 5.279 eV
- Discovery
- 1898 · Marie and Pierre Curie
Common uses
Cancer treatment, luminous paint, research
Did you know?
Discovered by Marie Curie and glows green in the dark.
Experiment with the elements
Radium doesn't form any compounds in our lab yet, but the periodic table sandbox lets you combine dozens of other real elements into real compounds — water, table salt, ammonia and many more — with their true chemical formulas.