The Element Krypton
[Click for Isotope Data]
Atomic Number: 36
Atomic Weight: 83.798
Melting Point: 115.79 K (-157.36°C or -251.25°F)
Boiling Point: 119.93 K (-153.22°C or -243.80°F)
Density: 0.003733 grams per cubic centimeter
Phase at Room Temperature: Gas
Element Classification: Non-metal
Period Number: 4 Group Number: 18 Group Name: Noble Gas
What's in a name? From the Greek word for hidden, kryptos.
Say what? Krypton is pronounced as KRIP-ton.
History and Uses:
Krypton was discovered on May 30, 1898 by Sir William Ramsay, a Scottish chemist, and Morris M. Travers, an English chemist, while studying liquefied air. Small amounts of liquid krypton remained behind after the more volatile components of liquid air had boiled away. The earth's atmosphere is about 0.0001% krypton.
The high cost of obtaining krypton from the air has limited its practical applications. Krypton is used in some types of photographic flashes used in high speed photography. Some fluorescent light bulbs are filled with a mixture of krypton and argon gases. Krypton gas is also combined with other gases to make luminous signs that glow with a greenish-yellow light. In 1960, the length of the meter was defined in terms of the orange-red spectral line of krypton-86, an isotope of krypton.
Once thought to be completely inert, krypton is known to form a few compounds. Krypton difluoride (KrF2) is the easiest krypton compound to make and gram amounts of it have been produced.
For those that are curious, pictures of krypton gas and krypton plasma can be found in the Questions and Answers section of this site.
Estimated Crustal Abundance: 1×10-4 milligrams per kilogram
Estimated Oceanic Abundance: 2.1×10-4 milligrams per liter
Number of Stable Isotopes: 5 (View all isotope data)
Ionization Energy: 14.000 eV
Oxidation States: 0
3s2 3p6 3d10