Group VIA The Chalcogens

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Group VIAThe Chalcogens

• By Van, Alex, Alex, and Logan

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Elements

• Oxygen
• Sulfur
• Selenium
• Tellurium
• Polonium
• Ununhexium

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Selenium (Se)

• Discovered in 1818 by Berzelius
• Named for Greek moon selene
• Atomic Number 34
• Atomic Mass 78.96
• Member of the Sulfur Family

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Properties
http//en.wikipedia.org/wiki/ImageSelen_1.jpg

• Exists in several allotropic forms, three
  generally recognized
• Red amorphous powder,
• Red crystalline material,
• Gray crystalline metal like form called metallic
  selenium.
• Red in powder form
• Black in vitreous form
• Crystalline monoclinic selenium is a deep red
• Crystalline hexagonal selenium, is a metallic
  gray

• http//www.lenntech.com/Periodic-chart-elements/Se
  -en.htm

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Properties continued

• Good photovoltaic and photoconductive
• Boiling Point 690ºC
• Melting Point 170 - 217ºC

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Uses

• Xerography for reproducing and copying documents
• Glass Industry
• Decolorize Glass
• Create ruby-colored glass
• Make enamels
• Rectifiers
• To make photocells, solar cells

www.colonialcandle.com
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Uses continued

• Photographic toner
• Additive to stainless steel

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Where it is Found?

• Very Rare
• Rarer than Silver
• Found in about 40 selenium containing minerals
  like copper, zinc and lead
• Selenium deficiency in the Northwest

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Polonium (Po)

• Highly rare and radio active
• Discovered in 1898 by Marie and Pierre Curie
• Atomic number 84
• Atomic mass 209

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Properties

• Volatile metal
• Radio active
• 254 C melting point
• 962C boiling point
• Cubic Structure

www.3dchem.com
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Uses
www.jaxa.jp

• Lightweight heat source for thermoelectric power
  in space satellites.
• Eliminating static charges in textile mills
• Brushes for removing dust from photographic films
  

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Where is it Found?

• Extremely rare
• Can created when you bombard natural bismuth with
  neutrons.

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Oxygen
Recognized by Antoine Lavoisier in 1777 Atomic
Number 8 Atomic Mass 15.999
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Where is Oxygen Found?

• Water
• H2O
• Air
• 20.95
• Plants
• photosynthesis end product
• Ozone
• Molecule consisting of three oxygen atoms

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Oxygens Forms

• Gas Liquid

Mineral
Example Cassiterite Made of tin and oxygen
Clear
Blue
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How is it Used?

• Necessary for life on Earth
• Accelerates Combustion
• Iron and Steel Industries

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Tellurium
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Basic Info

• Tellurium has an atomic weight of 127.60g
• Tellurium is a solid
• Tellurium has a grayish or metallic color

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Where is it found?

• Tellurium is not a commonly seen element but it
  is commercially available
• Tellurium is seen as a byproduct of copper

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Funny Fact

• Less than 0.0001 of Tellurium in the air will
  cause any living organisms to have garlic breath

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Sulfur
Sulfur 16 S 32.065

• Sulfur is solid at room temperature, and is
  bright yellow
• It is the tenth most common element
• In a certain form it will burn when mixed with O2

• Melts at 115 C
• Turns into a red liquid
• Boils at 444 C

• Burns with a blue flame
• While burning it emits sulfur dioxide

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Various Uses

• Sulfur powder is extractable from pyrite by the
  Frasch process, which uses hot water and air.
• Batteries, fireworks, preservatives
• Sulfuric acid
• Sulfur is used to vulcanize rubber
• Exists in most living cells

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Sources

• "Fact about Oxygen". September, 27, 2007
  lthttp//www.facts-about.org.uk/science-element-oxy
  gen.htmgt.
• "Oxygen uses". Pearson Education. September, 30,
  2007 lthttp//www.infoplease.com/ce6/sci/A0860185.h
  tmlgt.
• A Periodic Table of the Elements at Los Alsmos
  National Laboratory.1 Los Alamos National
  Laboratory's Chemistry Division. 30 Sep. 2007
  lthttp//www.periodic.lanl.gov/default.htmgt.
• "Selenium." Selenium (Se) -Chemical Porperties,
  Health and Environmental Effects.1 Lenntech. 30
  Sep. 2007 lthttp//www.lenntech.com/Periodic-chart-
  elements/Se-en.htmgt.
• And of course Wikipedia