1. Elements
   1. Chlorine
      1. yellow-green gas
   2. Flourine
      1. pale yellow
   3. Bromine
      1. brown liquid
   4. Iodine
      1. black shiny solid
   5. Halogens
      1. salt-maker
   6. diatomic molecules
      1. contain 2 atoms
      2. F2, Cl2, Br2, I2
2. Reactions
   1. + most metals
      1. salts
         1. In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of related numbers of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge)
      2. singly charged anion
      3. metals
         1. salts
         2. chlorine
            1. gold leaf
            2. catch fire in chlorine
            3. without heating
            4. iron
            5. iron(III) chloride fumes formed
            6. 2Fe (s) + 3Cl2 (g) ---> 2FeCl3 (s)
            7. chloride salts
         3. Flourine
            1. flouride salts
         4. Bromine
            1. bromide salts
         5. Iodine
            1. iodide salts
   2. +water
      1. salts
      2. Iodine
         1. very slow solubility
         2. I2 + Fe
            1. very slow
      3. halogens dissolve in water
         1. react with water
         2. solutions
            1. behave like bleaches
            2. chlorine
            3. pale yellow
            4. Bromine
            5. orange/brown
            6. Iodine
            7. brown
         3. Chlorine + water ---> hydrochloric acid + chloric(I) acid
         4. Cl2 (g) + H2O (l) ---> HCl (aq) + HClO (aq)
   3. electrons
      1. 7 outer energy level
      2. very reactive
   4. reactivity
      1. decreases down group
         1. atom bigger
         2. attractive force of nucleus less
         3. harder to gain electron
3. Displacement Reactions
   1. A displacement reaction is a type of reaction where part of one reactant is replaced by another reactant.
      1. more reactive hologen
         1. displaces less reactive halogen
   2. Chlorine (g)
      1. + sodium bromide (l)
         1. NaBr (aq) clear
         2. bromine displaced
         3. solution turns brown
            1. bromine
         4. Cl2 (g) + 2NaBr (aq) ---> 2NaCl (aq) + Br2 (aq)
      2. + sodium iodide
         1. NaI (aq) clear
         2. iodine displaced
         3. solution turns brown
            1. iodine
         4. Cl2 (g) + 2 NaI (aq) ---> 2NaCl (aq) + I2 (aq)
4. Uses
   1. flourides
      1. toothpastes
         1. prevent tooth decay
   2. flourine compunds
      1. plastics
         1. Teflon
   3. chlorofluorocarbons
      1. propellants
         1. aerosols
         2. refrigerators
      2. phased out
         1. effects on ozone layer
   4. chlorine
      1. bleach
   5. chlorine compounds
      1. kill bacteria
         1. drinking water
      2. antiseptics
   6. hydrochloric acid
      1. wide use in industry
   7. bromine compounds
      1. pesticides
   8. silver bromide
      1. photgraphic film
         1. light sensitive
   9. iodine solution
      1. antiseptic
5. Hydrogen Chloride / Hydrochloric Acid
   1. H2 (g) + Cl2 (g) ---> 2HCl (g)
      1. hydrogen chloride formed
         1. dissolve in water
            1. hydrochloric acid
            2. HCl (g) + H2O ---> H3O+ + Cl-
         2. methylbenzene
            1. no ions formed
            2. HCl not dissociate
            3. low electrical conductivity
         3. + ammonia gas
            1. white smoke
            2. ammonium chloride
            3. i.e. a test for either gas
         4. reverse reaction
            1. chlorine from HCl gas
            2. oxidizing agent
            3. manganese dioxide
            4. water
            5. removes fumes of HCl
            6. sulphuric acid
            7. dry the chlorine gas
            8. manganese dioxide + hydrochloric acid ---> chlorine + manganese chloride + water
            9. MnO2 + 4HCl ---> Cl2 + MnCl2 + H2O
            10. damp indicator paper
            11. bleached white by chlorine
            12. alternatively
            13. hydrochloric acid + potassium manganate (VII)
            14. 2KMnO4 (s) + 16HCl (aq) ---> 2KCl (aq) + 5Cl2 (g) + 2MnCl2 (aq) + 8H2O (aq)