Krypton
Definition and meaning of Krypton in chemistry.
![Krypton element card: symbol Kr, atomic number 36, atomic mass 83.798, electron configuration [Ar] 3d¹⁰ 4s² 4p⁶, oxidation states +2, Noble gas, group 18, period 4, gas at room temperature.](/assets/images/terms/krypton-chemical-element.webp)
Krypton is a noble gas chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, and completely tasteless gas under normal environmental conditions. It naturally occurs in very small trace amounts within the Earth's atmosphere.
In more detail
Krypton is a prominent member of group 18 on the far right of the periodic table. Every atom of krypton features a completely full valence electron shell. A valence shell is the outermost layer of electrons in an atom.
This full outer shell makes the gas exceptionally stable and chemically inert under standard conditions. Being inert means it does not easily react or bond with other chemical elements. Companies separate pure krypton from the atmosphere using a process called fractional distillation.
This complex industrial process carefully boils liquefied air to separate out the different gases. Scientists can force krypton to react only under extreme conditions of low temperatures and high electrical energy. They typically react it with highly electronegative elements like pure fluorine gas.
Fluorine pulls electrons strongly enough to form very fragile compounds like krypton difluoride, KrF2. When placed inside a low-pressure electrical discharge tube, krypton behaves uniquely. The applied electricity ionizes the trapped gas and makes it emit a brilliant greenish-white light.
Krypton is much heavier and significantly denser than regular breathable air. It also possesses a remarkably low ability to conduct thermal heat.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Kr |
| Atomic number | 36 |
| Atomic mass | 83.798 u |
| Category | Noble-Gas |
| State at room temperature | Gas |
| Discoverers | William Ramsay and Morris Travers (1898) |
Manufacturers frequently mix krypton with argon to fill energy-saving fluorescent light bulbs. The heavy gas improves the thermal insulation and extends the total lifespan of the bulb. Companies also heavily utilize the gas to produce high-speed photography flashes and specialized glowing neon signs.
Frequently asked questions
Is krypton completely unreactive in all situations?
No, while it forms no stable compounds under typical conditions, it can form fragile compounds like krypton difluoride when reacted with fluorine gas.
Where does the elemental name krypton come from?
The name comes directly from the Greek word kryptos, which translates to hidden. This reflects the massive difficulty the discoverers faced while trying to isolate it.
Related terms
Sources & references
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