Radium
Definition and meaning of Radium in chemistry.
Radium is a highly radioactive element denoted by the symbol Ra and atomic number 88. It represents the heaviest known alkaline earth metal in the periodic table. In its pure elemental form, it exhibits a brilliant silvery white appearance but rapidly oxidizes upon exposure to air.
In more detail
As a member of the alkaline earth metals located in group 2 of the periodic table, radium exhibits robust chemical reactivity closely mirroring that of barium. It occurs naturally in minute, trace amounts in uranium and thorium ores, notably within pitchblende deposits, where it is continually generated as an intermediate decay product of uranium. Radium is exceptionally luminescent, emitting a faint blue glow in the dark because its intense radioactivity constantly ionizes the surrounding nitrogen in the air. The pure metal reacts violently with water to form radium hydroxide and hydrogen gas, and it forms a black surface layer of radium nitride when exposed to the atmosphere. The element undergoes continuous radioactive decay to form radon gas, presenting extreme biological hazards and increasing the risk of bone cancer when handled without stringent safety precautions. Due to its unstable nucleus, radium continuously releases hazardous alpha, beta, and gamma radiation, with its most stable isotope possessing a half-life of approximately 1600 years.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Ra |
| Atomic number | 88 |
| Atomic mass | [226] u |
| Category | Alkaline Earth Metal |
| State at room temperature | Solid |
| Melting point | 700 degrees Celsius |
| Year discovered | 1898 |
Radium was historically used in self-luminous paints for watch dials and aircraft instruments until its severe health risks became widely known.
Frequently asked questions
Why does radium glow in the dark?
Radium emits radiation that excites nitrogen molecules in the surrounding air, causing them to emit a faint blue glow.
Is radium still used in everyday consumer products?
No, commercial use in everyday items ceased completely due to its extreme radioactivity and the severe health consequences associated with radiation exposure.