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• What is the physical state and color of fluorine (F2)?

  Very pale yellow gas
• What is the physical state and color of chlorine (Cl2)?

  Greenish, reactive gas
• What is the physical state and color of bromine (Br2)?

  Red liquid that gives off dense brown/orange poisonous fumes
• What is the physical state and color of iodine (I2)?

  Shiny grey solid that sublimes to purple gas
• What is the trend in melting and boiling points of halogens down the group?


  • Melting and boiling points increase down the group
  • Larger molecules have more electrons
  • Larger van der Waals forces require more energy to break
• What is the trend in electronegativity of halogens down the group?

  • Electronegativity decreases down the group
  • Atomic radii increase due to more shells
  • Nucleus less able to attract bonding electrons
• What is the relationship between oxidizing strength and halogens?

  • Stronger oxidizing agents displace weaker ones
  • Oxidizing strength decreases down the group
  • Chlorine displaces bromide and iodide ions
• What color solution indicates the presence of chlorine in a reaction?

  Very pale green solution
• What color solution indicates the presence of bromine in a reaction?

  Yellow solution
• What color solution indicates the presence of iodine in a reaction?

  Brown solution
• What are the displacement reactions of halide ions by halogens?

  • Chlorine displaces bromide and iodide
  • Bromine displaces iodide
  • Reactions can be represented as half equations
• What is the reaction of fluorides with silver nitrate?

  No precipitate is produced
• What precipitate is produced when chlorides react with silver nitrate?

  White precipitate
• What precipitate is produced when bromides react with silver nitrate?

  Cream precipitate
• What precipitate is produced when iodides react with silver nitrate?

  Pale yellow precipitate
• How can silver halide precipitates be differentiated?

  • Silver chloride dissolves in dilute ammonia
  • Silver bromide dissolves in concentrated ammonia
  • Silver iodide does not react with ammonia
• What is the role of nitric acid in the halide ion test with silver nitrate?

  • Reacts with carbonates to prevent Ag2CO3 formation
  • Ensures clear observations of halide precipitates
• What is the trend in reducing power of halides down the group?

  • Reducing power increases down the group
  • Larger ions have outer electrons that are easier to donate
• What happens when fluoride and chloride ions react with concentrated sulfuric acid?

  No redox reactions occur; only acid-base reactions
• What are the observations when NaF reacts with concentrated sulfuric acid?

  White steamy fumes of HF are evolved
• What are the observations when NaCl reacts with concentrated sulfuric acid?

  White steamy fumes of HCl are evolved
• What happens when bromide ions react with concentrated sulfuric acid?

  • Initial acid-base reaction produces HBr
  • Bromide ions reduce sulfur from +6 to +4 in SO2
  • Observations include white steamy fumes of HBr and orange bromine fumes
• What are the observations when iodide ions react with concentrated sulfuric acid?

  • White steamy fumes of HI are evolved
  • Black solid and purple fumes of iodine are produced
  • Colorless gas SO2 and yellow solid sulfur are also formed
• What is disproportionation in the context of chlorine reactions?

  • Chlorine simultaneously oxidizes and reduces
  • Example: Cl2 + H2O produces HClO and HCl
• What happens when chlorine reacts with water in sunlight?

  Produces O2 and Cl- ions, fading the greenish color of chlorine water
• What is the reaction of chlorine with cold dilute NaOH solution?

  • Cl2 reacts with NaOH to produce NaCl and NaClO
  • The solution fades to colorless
• How are chlorates and sulfates named in IUPAC convention?

  • Named with relevant oxidation number in Roman numerals
  • Examples: NaClO (sodium chlorate(I)), K2SO4 (potassium sulfate(VI))
• What is the oxidation state of sulfur in K2SO4?

  +6
• What is the oxidation state of sulfur in K2SO3?

  +4