Argon

Argon is an inert gaseous element. It is the third most prevalent noble gas in the earthís atmosphere. It is
present to the extent of .94% by volume. Itís symbol is Ar. The name Argon came from the Greek word
"argos" meaning "inactive". Argon is colorless and odorless. It is in group 18 on the periodic table. Itís
atomic number is 18 and itís atomic weight is 39,948 U. Argon melts at -189.3 degrees Celsius and boils at
-185.86 degrees Celsius. Argon is the third lowest in weight of the Nobel gases. Naturally occurring Argon
is composed of three isotopes. It has a gas density of 1.7837 g/l at 0 degrees Celsius. Argon has an
ionization energy 363 kcal/mol of atoms.. Heat of vaporization for Argon is 6.447 kJ/mole. Heat of fusion
for Argon is 1.188 KJ/Mol. Specific heat is .52 J/GK. The oxide is unknown. Argon is a nonmetal. Argon
doesnít appear to form true compounds however it is known to form a hydrate. Some ions have been
detected spectroscopically. For years, chemists thou!
ght that Nobel gases would not form chemical combinations with other elements and compounds. They
thought this because Nobel gas has itís outer most shell are completely filled with electrons. However, this
is not true. When the pressure and temperature is increased, the elements can be forced to form bonds.
Some examples are Krypton, Xenon, and Radon. Compounds with Argon, Helium, Neon are not likely to
form because the electrons are closely bounded to their nuclei. Argonís presence in the air was first
suggested by Henry Cavendish in 1785. It, however, was first separated by Lord Raleigh and Sir William
Ramsay in 1894.
Sir William Ramsay was a British chemist. He is known best for his isolation of elements out of
the atmosphere. In 1904 he was awarded the Nobel Peace prize in chemistry. Argon was the first of the 4
gases he discovered. Ramsay began to look for new gases when the learned that chemically prepared
Nitrogen is always lighter then Nitrogen prepared from air. He decided that there was a heavier gas in the
atmospheric Nitrogen. From there he found Argon. From liquid Nitrogen he and a colleague separated a
fraction in which they saw spectrscopically the presence of Neon.
John William Strutt Rayleigh also discovered Argon at the same time as Sir William Ramsay.
Argon is gotten commercially by the distillation of liquid air. It is used to fill electric light bulbs. If air is
left in incandescent bulbs, the filament burns; if the bulb is evacuated (that was how it was it was in the
past) the tong stem filament tends to evaporate. When that happens the whole inside of the bulb turns black.
To prevent this evaporation the bulb can be filled with Nitrogen or with Argon, which is better. This is true
because it is a poor conductor of heat and cools the filament less.
Other uses of Argon are in florescent tubes, photo-tubes, and glow tubes. Argon is also used as an
inert gas shield for electric arc welding and cutting, as a blanket for the production of reactive elements,
like Titanium. It is also used as an inert gas atmosphere for growing Silicon and Germanium crystals.
Argon is also used in one type of Neon lamp. Argon gives off a blue light. Argon tubes require a smaller
amount of energy then do normal Neon tubes, because of this, small amounts of Argon are sometimes
mixed with Neon. This is cheaper because it saves money. Argon is also used in electric-arc technology
and lasers.