Group 7 Elements

• What are group 7 elements known as


  Halogens
• Describe fluorine


  Very reactive, poisonous yellow gas
• Describe chlorine


  fairly reactive, poisonous, dense green gas
• Describe bromine


  Dense, poisonous, red-brown volatile liquid
• Describe iodine


  dark grey crystalline solid or purple vapour
• Trends of group 7


  As you go down:

  1. less reactive since it's harder to gain an extra electron
  2. higher melting and boiling points
  3. higher relative atomic masses
• What do halogens form

  Molecular compounds
• What do halogens form with metals

  Ionic bonds
• What is a displacement reaction with halogens

  A more reactive halogen replaces the salt of a less reactive one
• Cl2 + 2KI

  I2 + 2KCl