group 7 & group 0

• What are the elements in group 7 of the periodic table called?

  Halogens
• How many electrons do halogens have in their outer shell?

  7 electrons
• Why are halogens very reactive?

  They easily accept an electron into their outer shell
• What happens when halogens react?

  They gain 1 electron for a full outer shell
• What type of ions do halogens form when they gain an electron?

  Negative ions
• What are diatomic molecules?

  Molecules made of pairs of atoms
• How are salts formed in relation to halogens?

  A metal atom transfers its outer electron to a non-metal atom
• What happens to the ions in a salt compound?

  All the ions have a full outer shell
• How does reactivity change as you go down group 7?

  Halogens become less reactive
• Why do halogens become less reactive down the group?

  More electron shells are gained, increasing distance
• What is the color and state of chlorine at room temperature?


  Pale green gas
• What is the color and state of bromine at room temperature?

  Red-brown liquid
• What is the color and state of iodine at room temperature?

  Dark grey solid
• What are the elements in group 0 of the periodic table called?

  Noble gases
• Why are noble gases unreactive?

  They have a full outer shell of electrons
• How can noble gases be used in light bulbs?

  They do not react with the hot filament
• What is the atomic structure of noble gases?

  They exist as single atoms (monatomic)
• What is the boiling point trend of noble gases?

  Boiling points increase down the group
• Why do noble gases have low densities?

  They have low relative atomic mass
• How does the density of noble gases change down the group?

  Densities increase as relative atomic mass increases
• What are the properties of halogens at room temperature?

  • Chlorine: pale green gas
  • Bromine: red-brown liquid
  • Iodine: dark grey solid
• What are the properties of noble gases?

  • Inert: full outer shell of electrons
  • Monatomic: exist as single atoms
  • Low boiling points: increase down the group
  • Low density: increases down the group