Essay/Term paper: Krypton

Essay, term paper, research paper:  Medicine

I am the chemical element known as Krypton. I
can also be referred as Kr. I will be telling you
about my history, my properties, my family and my
occurrence. I will also be telling you about my
uses and ores, also the analytical methods based
on me.

I received the name krypton from the Greek word
"hidden" because I was hiding for so long,
undetected. I am from a rare group of gases called
noble gases. The other noble gases are helium,
xenon, neon, argon and radon. I was discovered
in England in 1898 almost 100 years ago by Sir
William Ramsey and Morris W. Travers. They
found me in the less volatile part of inert-gas
mixture left after oxygen had been chemically
removed from a sample of air. I am about one
millionth of the earth's atmosphere. Only about 2 x
10-8% of the weight of the earth am I. I am a
colorless, odorless and tasteless gas. My atomic
number is 36. My atomic weight is 83.80. My
melting point is -157.20°C or -251.5°F. My gas
density at 0°C is 3.749 g/liter. My valence is 0,2.
Many of my physical properties differ according to
various scientists. The outer shell of my atom is
filled with electrons in a stable structure. That is
why there is only one atom in my element. No one
yet has prepared a chemical compound for me
that is stable at room temperature. I can be
trapped in crystals of different host compounds to
form a clathrate. The radioactive isotopes of me
known to this point are 76Kr, 77Kr, 79Kr, 81Kr,
83Kr, 85Kr, 87Kr-95Kr and 97Kr. My isotopes are
produced as by-products of nuclear fission of
uranium in nuclear reactors. They can also be
formed in particle accelerator such as the
cyclotron. Until 1962, I, like other members of my
noble gas family, was thought to be chemically
inert. Even now the only well known
characteristics of my compound are diflouride,
KrF2, and its complexes. The diflouride can be
prepared by passing an electric discharge through
a 1:1 mixture of gaseous fluorine and me at -188°
C. After the reaction is complete, the reactor will
be warmed and put into a glass vessel. I arise in
the earth's soil, through the breakdown of uranium,
but not the radioactive breakdown though. That
may be why I am very similar to another noble
gas, Xenon. Also, the mixture of stable and
radioactive isotopes of me are produced in nuclear
reactors by the slow neutron fission of uranium.
The only stable source for me is air. The content
of my gases can be detected and determined by
gas chromatography. Before scientists had these
methods of determining my content, they obtained
it by passing a gas sample through an electric
discharge tube at low pressures and analyzing the
light with a spectrometer. The principle and most
common use for me in the world is in filling electric
lamps and electronic devices of various types. I
am used to fill greenish fluorescent lights. Both
Argon and I can be used to fill lamps with light.
My radioactive 85 is used in leak testing of sealed
containers. Another use for me is continuous
measurements, determining thickness of materials,
such as paper. I hope you have learned a little bit
more about such a small element like me.