Chalcogens

• Other Names of Oxygen

  • Yne
  • Dephlogisticated Air (J. Priestly)
  • Empyreal Air (L.W. Scheele)
• Lavoisier was the one who named the element, Oxygen.
• Etymology of Oxygen

  • Oxys = “sharp” or “sour”
  • Gene = “one that produces”
  • Greek meaning: “Acid-former” or “Acid-producer”
• Oxygen

  • Most abundant element on Earth
  • Stored in a green container
• Hydrogen peroxide (H2O2)

  • Thenard’s oxygenated acid
  • AKA: Agua oxygenada
  • 3% H2O2 = 10volume
• Allotropes of Oxygen

  • O2
  • O3 (Ozone = “to smell”)
• Commercial Manufacture of Oxygen:

  • Fractional distillation of liquefied air – Linde Process
  • Electrolysis of water
  • Boussingault–Brin Brothers’ Process – obsolete
  • Thessie du Motay–Marechal process
• Other Names of Sulfur

  • Azufre
  • Sufra (Yellow)
  • Brimstone
  • Shulbari
• Sulphur is derived from Sanskrit word “shulbari” meaning enemy (ari) of copper (shulba).
• In Sicily, sulfur is recovered in a crude furnace called a “calcarone”
• Allotropes of Sulfur:

  • Rhombic Sulfur or α-Sulfur
  • Monoclinic Sulfur or β-Sulfur
  • Liquid sulfur – Heating sulfur at 160⁰C
• Plastic Sulfur


  A variety of sulfur that resembles rubber and is insoluble in carbon disulfide
• Amorphous Sulfur


  Hard and brittle, soluble in carbon sulfide
• Sublimed sulfur

  • AKA: Flowers of Sulfur
  • Uses: Treatment for acne, seborrhea, psoriasis
• Precipitated sulfur

  • AKA: Milk of Sulfur, Lac sulfur
  • Uses: Use in sulfur ointment, treatment for scabies
• Washed sulfur


  This form of sulfur is prepared when sublimed sulfur is treated with ammonia and washed with water to remove impurities such as arsenic.
• Uses of Sulfur

  • Cathartic
  • Treatment for scabies
  • Depilatory agent
  • Fumigant
  • Miscellaneous skin diseases
• Selenium

  • Came from the Greek word selene, meaning “moon”.
  • Discovered by Berzelius
  • Essential trace element
  • Promotes absorption of Vitamin E
• Use of Selenium

  Production of red glass, rubber industry
• Selenium Disulfide (SeS2; Selsun Blue)


  Antidandruff (2.5%)
• Tellurium


  Came from the Latin word tellus meaning, “Earth”
• Use of Tellurium

  Anti-diaphoretic (suppresses night sweats)
• Polonium

  • The first element discovered by Marie Curie.
  • Named after the country, Poland.
• Chromium

  • Essential trace element
  • Glucose tolerance factor
• Deficiency of Chromium

  Chromium with the addition of Sodium hydroxide produces greygreen precipitate.
• Use of Potassium Dichromate (K2Cr2O7)

  Powerful oxidizing agent
• Molybdenum

  • Essential trace element
  • Co-factor enzyme
• Use of Molybdenum Oxide (MoO3)


  MOL-IRON (Molybdenum oxide + Ferrous sulfate)
• Uranium

  • First radioactive element discovered by Henri Becquerel.
  • It is used in the manufacture of atomic bombs.