Krypton, represented by the chemical symbol Kr, is a chemical element that belongs to group 18 (VIII A) of the periodic table. It belongs to the group of noble gases, along with helium, neon, argon, xenon, and radon. It is a colorless, odorless, and tasteless gas, which has an atomic number of 36.
Krypton, along with xenon and neon was discovered by Sir William Ramsay (a Scottish chemist and physicist) and Morris William Travers, an English chemist, in 1898. These elements were discovered by the technique of evaporating almost all components of liquid air. During the process of evaporation, each component evaporated and was collected separately. On analyzing the different components obtained by this process, a completely new element was discovered, which was subsequently named krypton.
Interesting Facts about Krypton
Krypton occurs in trace amounts in the atmosphere, approximately one parts per million.
- The name Krypton is derived from a Greek word 'kryptos', which means 'hidden'.
- This element has an atomic weight of 83.798 and is present in period 4 of the periodic table.
- The melting point of krypton is -157.4ºC. It has a boiling point of -153.2ºC, with a density of 3.75 grams per liter.
- It has 31 isotopes in all, out of which 5 are considered stable and the rest are radioactive.
- The half life of the radioactive form of this element is 81(Kr) is 250,000 years.
- It is produced in the Earth's crust as a result of radioactive decay of thorium and uranium.
- As most of the nuclear reactors are located in the northern hemisphere, the concentration of this element at the north pole is about 30% higher, than that at the south pole.
- The element Krypton is characterized by emission of sharp spectral lines, out of which the green and yellow lines are the strongest and most prominent.
- When ionized, krypton gas emits bright white light, and hence Kr-based bulbs are widely used in high speed photography. It is also used in slide and movie projectors.
- This element, like other inert gases, is used in making luminous, fluorescent lights used in different kinds of lamps, incandescent light bulbs, advertising signs, etc.
- One of the radioactive isotopes of krypton can be combined with phosphorus to produce materials that glow or shine in the dark.
- Krypton-85 is used to study the flow of blood in the human body. When this gas is inhaled, it is absorbed by the blood and travels through the bloodstream and the heart, along with blood. The pathway can be determined by holding a detection device over the person's body.
- This noble gas is used in the manufacture of quasi-homogeneous electromagnetic calorimeters that are used to measure the quantity of heat.
- An interesting application of this gas was in defining a meter. Krypton-86, on heating, gives off a clear bright line, which is reddish yellow in color. Between the period of 1960 and 1980, scientists defined meter as 1,650,763.73 times the width of this line produced by this element.
- This element is considered to be one of the inert gases, which means it is chemically inactive. However, its compounds have been synthesized in the laboratory, and these synthetic compounds are used for research purposes.