Chemical Formula
Ra
Background
In 1898, Marie Sklodowska Curie and Pierre Curie discovered radium while studying the radioactivity in pitchblende. They found that the mineral was still radioactive even after removing uranium from it. With a suspicion that the ore may contain another radioactive element, they refined several tons of pitchblende and obtained small amount of radium in the form of radium bromide. Later, Andre Debierne and Marie Curie isolated metallic radium in 1910 by electrolyzing pure radium chloride solution. The name of the element comes from the Latin word "radius" which means ray.
Basic Information
| Name |
Radium |
| Symbol |
Ra |
| Atomic number |
88 |
| Atomic weight |
226 amu |
| Standard state |
Solid at 298 K |
| CAS Registry ID |
7440-14-4 |
| Group in periodic table |
2 |
| Group name |
Alkaline earth metal |
| Period in periodic table |
7 |
| Block in periodic table |
s-block |
| Color |
Metallic |
| Classification |
Metallic |
| Melting point |
973 K (700°C or 1292°F) |
| Boiling point |
1413 K (1140°C or 2084°F) |
| Density |
5 g/cm3 |
| Phase at room temperature |
Solid |
Occurrence
Radium is present in the Earth’s crust in very small quantities. It occurs in almost all uranium ores including pitchblende.
Radium - Periodic Table of Videos
Isotopes
Around 33 isotopes of radium have been discovered so far with mass numbers ranging from 202Ra to 234Ra. None of them are stable. The longest-lived isotope of radium is 226Ra with a half-life of 1602 years.
Production
Uranium ores are the chief sources of radium. The ore is crushed and dissolved with sulfuric acid. The resulting precipitate contains barium salts, radium salts and other compounds which are treated with hydrochloric acid or carbonates to produce a solution containing barium bromide and radium bromide. The radium bromide is concentrated through crystallization and filtration to obtain radium.
Key Properties
The key properties of radium include the following:
- It is a silvery-white metal
- It is highly radioactive
- It rapidly reacts with nitrogen when exposed to air
- It quickly reacts with water to form radium hydroxide
- It has chemical properties similar to that of the other alkali earth metals.
Applications
Some of the applications of radium are listed below:
- It is used in the production of luminous paints
- It is used in medicine to produce radon gas for treating cancer.
References
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