Halogens and Noble Gases

• What are the group seven elements known as?

  Halogens
• What are the group zero elements known as?

  Noble gases
• What are the properties of halogens?

  • Fluorine: poisonous yellow gas, very reactive
  • Chlorine: poisonous green gas, less reactive
  • Bromine: reddish-brown volatile liquid, poisonous
  • Iodine: dark gray solid, forms poisonous purple vapors, also an antiseptic
• What is the state of iodine at room temperature?

  Dark gray solid
• What is a diatomic molecule?

  A molecule consisting of two atoms
• How do halogens form diatomic molecules?

  By sharing electrons and forming covalent bonds
• What type of structures do halogen compounds form with non-metals?

  Simple molecular structures
• What happens to the melting and boiling points of halogens as you go down the group?

  They increase
• How does reactivity change among halogens as you go down the group?

  Reactivity decreases
• Why does reactivity decrease in halogens as you go down the group?

  The outermost shell gets further from the nucleus, weakening the attractive force
• What do we call a halogen that gains an electron?

  Halide
• What are the names of the halides formed from halogens?

  Fluoride, chloride, bromide, iodide
• With which group do halogens most often form ionic compounds?

  Alkali metals in group 1
• What is a displacement reaction involving halogens?

  A more reactive halogen displaces a less reactive one
• What happens when chlorine gas is pumped into a solution of potassium bromide?

  Chlorine displaces bromine to form potassium chloride
• What is the state of noble gases at room temperature?

  Colorless gases
• Why are noble gases considered inert?

  They have full outer shells and do not react with other atoms
• What happens to the boiling points of noble gases as you go down the group?

  They increase
• What are the key characteristics of noble gases?

  • Exist as colorless gases
  • Inert due to full outer shells
  • Exist as single atoms
  • Non-flammable