Halogens Group VII A

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HalogensGroup VII A

• Mackenzie Entrikin
• Molly Doran
• Eric Neiman
• Drew Peterson

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Fluorine

• Used in the making of uranium
• Small amounts of fluorine in drinking water and
  toothpaste help prevent tooth decay. Fluorine is
  added to city water supplies in the proportion of
  about one part per million to help prevent tooth
  decay
• Used in air conditioning and refrigeration
• Hydrofluoric acid etches glass
• It is used in rocket fuels
• Fluorine is found as a pale yellow gas in nature.
  This gas is usually very volatile and poisonous.

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Chlorine

• Chlorine is found in nature as a green gas. This
  gas is 2.5 times as dense as regular air.
• water purification
• used in the production of paper products,
  dyestuffs, textiles, petroleum products,
  medicines, antiseptics, insecticides, food,
  solvents, paints, plastics, and many other
  consumer products.
• bleaching and sanitation
• Chlorine is a toxic gas that irritates the
  respiratory system.

4
Bromine

• Bromine evaporates easily to a red vapor, and is
  a volatile liquid at room temperature.
• fumigants
• flameproofing agents
• water purification
• dyes
• medicines
• pesticides

5
Iodine

• Iodine is found dissolved in sea water.
• disinfectant for external wounds
• silver iodide is used in photography
• nutrient
• added to table salt for nutrition

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Astatine

• Astatine is the rarest natural element on earth.
  Only .9 oz of Astatine is found in the earths
  crust at one time. The half-life of Astatine is
  8 hours and 6 minutes.
• There are no known uses for Astatine.

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How Fluorine and Other Halogens React With Other
Elements

• Fluorine is the most reactive and most
  electronegative of all the elements
• It is so reactive that glass, metals, and even
  water, as well as other substances, burn with a
  bright flame in a jet of fluorine gas.
• It even reacts with noble gases krypton, xenon,
  and radon and noble metals gold and platinum
• All halogens have seven valence electrons

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Continued

• They have very large ionization energies and very
  strong shielding, making it very hard to take an
  electron from them because it holds onto its
  electrons so strongly
• Halogens almost always take one electron away
  from elements in other groups
• This gives the halogen a full valence shell of
  eight electrons
• In doing this, it achieves its most stable
  state and its state of lowest energy

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Chemical Tendencies

• All halogens are electronegative and reactive
• As you move toward smaller atoms, the
  electronegativity gets stronger
• Halogen atoms tend to grab one electron from
  another atom and then bond ionically to it
• Some halogens can even bond to some of the higher
  noble gases (krypton, xenon, etc.)
• Halogens have one covalent bond

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Fluorine Chemistry

• Fluorine is the most electronegative and reactive
  element known. It is one of the few substances
  that can corrode glass
• It can even strip electrons off higher halogens
• Most substances burn with a bright flame in
  fluorine gas
• Fluorine-metal salts are extremely stable

Iodine heptafluoride molecule
Calcium difluoride (fluorite) crystal