Inert Gases and Characteristics
• The inert gases are obtained by fractional
distillation of air.
• They are often used aboard chemical tankers and
product carriers (smaller vessels).
• Helium, Neon, Argon, Krypton, Xenon, Radon and
are inert gases.
• Duplet (Helium) or Octet
• Full valence shell
Weak interatomic force
Very low melting and boiling points.
Monatomic gases under standard conditions
Helium has several unique qualities when compared
with other elements:
– Boiling and melting points are lower than those of any
other known substance
– Only element known to exhibit super fluidity
– Only element that cannot be solidified by cooling under
standard conditions—a pressure of 25 standard
atmospheres (2,500 kPa; 370 psi) must be applied at a
temperature of 0.95 K (−272.200 °C; −457.960 °F) to
convert it to a solid.
• Noble gas is translated from the German noun
Edelgas, first used in 1898 by Hugo Erdmann to
indicate their extremely low level of reactivity.
• The name makes an analogy to the term "noble
metals", which also have low reactivity.
• Pierre Janssen and Joseph Norman Lockyer
discovered a new element on August 18, 1868 while
looking at the chromosphere of the Sun, and named
it helium after the Greek word for the Sun, ήλιος
(ílios or helios).
• Lord Rayleigh theorized that the nitrogen extracted
from air was mixed with another gas, leading to an
experiment that successfully isolated a new
element, argon, from the Greek word αργός (argós,
• With this discovery, they realized an entire class of
gases was missing from the periodic table.
• During his search for argon, Ramsay also managed
to isolate helium for the first time while heating
cleveite, a mineral.
• In 1902, having accepted the evidence for the
elements helium and argon, Dmitri Mendeleev
included these noble gases as group 0 in his
arrangement of the elements, which would later