Element 88
Radium
Alkaline earth
Radium (Ra) is in the s-block of the periodic table — group 2, period 7.
Radium is a chemical element with symbol Ra and atomic number 88.
Key data
- Atomic number
- 88
- Atomic mass
- 226.000 u
- Group / Period
- 2 / 7
- Block
- s-block
- Phase at STP
- Solid
- Density
- 5.5 g/cm³
- Melting point
- 959.9 °C
- Boiling point
- 1736.8 °C
- Electron configuration
- [Rn] 7s2
Periodic table block
Radium is in the s-block (group 2, period 7). Elements land in the s-block when their highest-energy electrons fill an s subshell — this includes hydrogen, helium, and the reactive metals on the far left of the table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Glow-in-the-dark paints (historical)
- •Cancer therapy
- •Highly radioactive
Discovery
Year: 1898
Discovered by: Pierre Curie
Frequently asked questions
What is the atomic number of Radium?
Radium has atomic number 88. Its symbol is Ra and its atomic mass is 226 u.
What category of element is Radium?
Radium is classified as alkaline earth. It sits in group 2, period 7 of the periodic table.
What block of the periodic table is Radium in?
Radium is in the s-block (group 2, period 7). Its highest-energy electrons occupy the s subshell — you can see this in its electron configuration, [Rn] 7s2.
What is Radium used for?
Common uses of Radium include: Glow-in-the-dark paints (historical), Cancer therapy, Highly radioactive.
When was Radium discovered?
Radium was discovered in 1898 by Pierre Curie.
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