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					                            Argon
 By Lauren Ciocca, Cynthia
Gagliardi, and Dana Civitello
                      Basic Information
   Atomic Number:18
   Atomic Mass: 39.948(1) amu
   Symbol: Ar
   Subatomic Particles: 18 electrons, 18 protons, 22
    neutrons
   Isotopes: Ar-36 Ar-38 Ar-40
   Electron Configuration: [Ne]3s23p6
   Pure Form: Colorless odorless tasteless nontoxic
    gas
   Physical State at Room Temperature: gas
   Common in Nature: makes up 0.93 % of the earth’s
    atmosphere third most abundant. It has increased
    since the earth was created because Potassium
    that is radioactive decays and forms Argon.
   Where found in Nature: In the air as a by product of
    Nitrogen and Oxygen.
   How to make pure samples: from fractional
    distillation of liquid air
   Does not form compounds
                       Common Uses

   Used in electric light bulbs, and
    florescent tubes
    Filling phototubes, and glow tubes
    Used as an inert gas shield for arc
    welding and cutting
    Crystals in the semiconductor industry
    are grown in argon atmospheres
   A blanket for the production of
    radioactive elements
    Makes argon lasers that are used in
    holography, eye surgery,
    spectrochemistry, optical image
    processing, semiconductor processing,
    and laser light shows
                                   History
   From the Greek word argon meaning
    inactive. It was discovered in 1894 by Sir
    William Ramsay, a Scottish chemist, and
    Lord Rayleigh, an English chemist.
   Lord Rayleigh noticed that a liter of pure
    nitrogen from air weighed more than a
    liter of nitrogen from a compound
   He concluded another gas was present
   Many gases were present such as helium,
    neon, krypton, xenon, as well as argon
   Eventually Ramsey obtained argon by
    examining the left over elements in air
    after removing nitrogen, oxygen, carbon      Lord Rayleigh (above),
    dioxide and water                            William Ramsay (left)
       Air has 0.93% argon
                  Argon in Light Bulbs
   Incandescent bulbs
      •  Vacuum or inert gas must be used in the bulb
      •  Argon- inert gas, inexpensive, does not conduct a
         lot of heat
      •  Replaces air that causes bulbs to blacken and
         burn out by preventing the metal from hitting air
      •  Sometimes mixed with nitrogen
           • Sometimes replaces nitrogen (very inert)

      •  Use of gas makes it possible for the filament to be
         at a higher temperature
      •  Light more visible
      •  Argon filled light bulbs usually last longer
           • 120 watt bulbs (over 60 watts) contain gases
               like argon
•   Gas Discharge Tubes (Neon Bulbs) and Florescent
    Lighting
      •   Mixed with neon or mercury
      •  Produces a blue or violet glow
                             Argon Lasers
Click for video




      An ion laser (popular)                   •Discharge tube- normally made of materials
                                                with low heat conductivity
         Used for scientific and medical
            purposes, artistic/light shows      •Emits 1 to 20 Watts of flux
      Produces nine different wavelengths
                                                •Advantages include: little noise, easy to aim
         Blue spectrum wavelength- common
                                                beam, cost, long lasting
      Large amount of power necessary
      Argon atoms become ionized and excited   •Used often for eye surgery, holography,
      Magnetic field around laser tube         spectrochemistry, optical imaging, and
                                                semiconductor processing, printing, copying,
         Prevents loss of electrons
                                                scanning
                         Glossary
   Arc Welding- welding that uses an electrical arc to provide
    heat
   Discharge Tube- a closed insulating vessel containing a
    gas at low pressure through which an electric current flows
    when sufficient voltage is applied to its electrodes
   Distillation- the evaporation and subsequent collection of a
    liquid by condensation as a means of purification
   Holography- a method of producing a three-dimensional
    image of an object by recording on a photographic plate or
    film the pattern of interference formed by a split laser beam
    and then illuminating the pattern either with a laser or with
    ordinary light
   Inert- not readily reactive with other chemical elements;
    forming few or no chemical compounds
                                      Glossary cont.
   Ionized- converted totally or partly into ions
   Filament- A fine wire heated electrically to incandescence in an
    electric lamp
   Flux- radiant energy in the visible-wavelength range
   Liquid air- air in its liquid state, intensely cold and bluish, obtained by
    cooling and compression.
   Spectrochemistry- a branch of chemistry based on a study of the
    spectra of substances
                             Bibliography
   Dictionary.com. 2005. Lexico Publishing Group, LLC. <www.dictionary.com>
   Element Displays. 2004. The Red Green & Blue Company.
            <http://www.theodoregray.com/PeriodicTableDisplay/Elements/018/index.s12.html>
   Chem4Kids. 1997-2005. Andrew Rader Studios.
            <http://www.chem4kids.com/files/elements/018_shells.html>
   http://vcs.abdn.ac.uk/ENGINEERING/lasers/gas.html
   Bulbs.com. 2005. Illuminating Engineering Society of North America.
            <http://www.bulbs.com/lightingguide/tech_incandescentdiagram.asp>
   Boyer, Matt. Argon Laser. 1992-2000. Matt Boyer.
            <http://www.angelfire.com/la3/lasers/argonlaser.html>
   www.en.wikipedia.org/Wiki/Argon
   http://www.ucl.ac.uk/news/library/images/ramsay.jpg
   Goldwasser, Samuel M. Argon/Krypton Lasers. 1994-2005. Samuel M. Goldwasser.
            <http://repairfaq.ece.drexel.edu/sam/laserarg.htm>
   www.Pearll.lanl.gov/periodic/elements/18.html
   Chemistry Web Elements. 1993-2005. Mark Winter.
            <www.webelements.com/webelements/scholar/elements/argon/history.html>
   www.Nautilus.fis.uc.pt/st2.5/scenes-e/elem/e01810.html
   http://www.ioa.org.uk/publications/web_articles/pioneers_of_acoustics/rayleigh/rayleigh.html

				
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