Krypton
Definition and meaning of Krypton in chemistry.
Krypton is a noble gas chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, and completely tasteless gas that naturally occurs in very trace amounts within the Earth's atmosphere.
In more detail
As a prominent member of group 18 on the periodic table, krypton is characterized by its completely full valence electron shell, making it exceptionally stable and chemically inert under standard conditions. It is industrially separated from the atmosphere through the meticulous fractional distillation of liquefied air. Under extreme conditions of low temperatures and energetic excitation, it can be forced to react with highly electronegative elements like fluorine to form compounds such as krypton difluoride, KrF2. When it is ionized in a low-pressure electrical discharge tube, krypton emits a brilliant, high-intensity greenish-white light. Its density is significantly higher than that of regular air, and it possesses a remarkably low thermal conductivity.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Kr |
| Atomic number | 36 |
| Atomic mass | 83.798 u |
| Category | Noble Gas |
| State at room temperature | Gas |
| Boiling point | -153.4 degrees Celsius |
| Melting point | -157.4 degrees Celsius |
| Discoverers | William Ramsay and Morris Travers (1898) |
Krypton is frequently mixed with argon as a filling gas for energy-saving fluorescent lights, and it is also heavily utilized in the production of high-speed photography flashes and specialized glowing signage.
Frequently asked questions
Is krypton completely unreactive in all situations?
No, while it is generally considered inert and forms no stable compounds under typical conditions, it can form a few fragile compounds like krypton difluoride when reacted with fluorine gas at very low temperatures.
Where does the elemental name krypton come from?
The name is derived directly from the Greek word kryptos, which translates to hidden, reflecting the immense difficulty the discoverers faced while trying to isolate it from liquid air.