Radium (Ra)
Radium (Ra, element 88) is an alkaline earth metal in group 2, period 7. Atomic mass 226, electron configuration [Rn] 7s², uses and facts.
About Radium
Radium is an alkaline earth metal with the symbol Ra and atomic number 88. It is a solid at room temperature, and it sits in group 2, period 7 of the periodic table. Radium was discovered in 1898 by Marie & Pierre Curie.
Radium key facts
- Atomic number: 88
- Symbol: Ra
- Atomic mass: 226 u
- Category: alkaline earth metal
- Group: 2
- Period: 7
- State at room temperature: solid
- Electron configuration: [Rn] 7s²
- Electronegativity (Pauling): 0.9
- Melting point: 973 K (699.85 °C)
- Boiling point: 2010 K (1736.85 °C)
- Density: 5.5 g/cm³
- Common oxidation states: +2
Electron configuration
The electron configuration of radium is [Rn] 7s². The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells. Radium has 2 valence electrons.
Uses of radium
- Cancer treatment (historical)
- Luminous paint (historical)
- Research
Did you know?
Marie Curie's notebooks are still radioactive and kept in lead-lined boxes. You need protective gear to read them.
Other elements in group 2 and neighbours
Frequently asked questions
What is the atomic number of radium?
The atomic number of radium is 88, which means every radium atom has 88 protons.
What is the electron configuration of radium?
The electron configuration of radium is [Rn] 7s².
What group and period is radium in?
Radium is an alkaline earth metal in group 2, period 7.
What state is radium at room temperature?
Radium is a solid at room temperature.
What is radium used for?
Radium is used for cancer treatment (historical), luminous paint (historical), research.