Krypton is a chemical element with chemical symbol Kr, and atomic number is 36 . It is a rare gas of Group 18 of the periodic table, which forms relatively few chemical compounds. About three times heavier than air, It is colourless, odourless, tasteless, and monatomic. Although traces are present in meteorites and minerals, It is more plentiful in Earth’s atmosphere, which contains 1.14 parts per million by volume of Kr. The element was discovered in 1898 by the British chemists Sir William Ramsay and Morris W. It is named from the Greek word kryptos, Which means “hidden”.
Properties and Characteristics of Krypton
- Its boiling point is about 30–40 °C (50–70 °F) higher than those of the major constituents of air, Kr is readily separated from liquid air by fractional distillation; it accumulates along with xenon in the least volatile portion. These two gases are further purified by adsorption onto silica gel, redistillation, and passage over hot titanium metal, which removes all impurities except other noble gases.
- It used in certain electric and fluorescent lamps and in a flashlamp employed in high-speed photography. Radioactive Kr-85 is useful for detecting leaks in sealed containers, with the escaping atoms detected by means of their radiation.
- Natural krypton is a mixture of six stable isotopes, Kr-84 (57.0 percent), Kr-86 (17.3 percent), krypton-82 (11.6 percent), krypton-83 (11.5 percent), krypton-80 (2.25 percent), and krypton-78 (0.35 percent).
- It has isotopes of every mass number from 69 through 100; of these isotopes; twenty-five are radioactive and are produced by fission of uranium and by other nuclear reactions. The longest lived of these, krypton-81, has a half-life of 229,000 years.
- After it has been stored a few days, Kr obtained by nuclear fission contains only one radioactive isotope, Kr-85, which has a half-life of 10.8 years, because all the other radioactive isotopes have half-lives of 3 hours or less.