Halogens
- Created by: KatieL
- Created on: 29-12-12 18:33
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- Halogens
- Group 7
- Flourine; Chlorine; Bromine; Iodine; Astatine
- Flourine- highly reactive not counted in all the trends
- Astatine- radioactive
- All have 7 electrons in their outer shell
- Found as X2 simple covalent molucles
- Flourine; Chlorine; Bromine; Iodine; Astatine
- Trends
- Reactivity
- Decreases as you down the group
- Distance from the nucleus increases, harder to gain an extra electron
- Decreases as you down the group
- Atomic Radius
- Increases as you go down the group
- More electrons, so more energy levels
- Increases as you go down the group
- Melting/ Boiling Point
- Increases as you go down the group
- More electrons so the dipole is larger and the Van der Walls forces are larger
- Increases as you go down the group
- Reducing power
- Displace other halide ions
- Decreaes down the group
- Reactivity decreases
- Decreaes down the group
- Displace other halide ions
- Reactivity
- Testing for Halides
- Cyclohexance
- Cyclohexane layer changes colour
- Chlorine- yellow/green
- Bromine- Orange/Brown
- Iodine- Purple
- Cyclohexane layer changes colour
- Silver Nitrate
- Forms a precipitate
- Chlorine- White ppt. dissolves in dilute ammonia
- Bromine- Cream ppt. Dissolves in conc. ammonia
- Iodine- Yellow ppt. Insoluble
- Ag+ + X- --> AgX
- Forms a precipitate
- Cyclohexance
- Disproportionation
- Both oxidised and reduced in the same reaction
- Reaction with Sodium Hydroxide
- Cold
- X2 + 2 NaOH --> NaXO + NaX + H2O
- Hot
- 3X2 + 6NaOH --> NaX03 + 5NaX + 3H2O
- Cold
- Reaction with Sodium Hydroxide
- Both oxidised and reduced in the same reaction
- Uses
- Chlorine is used to clean water as it kills most bacteria
- Flouride is put in toothpaste
- Hydrogen Floride is used to etch glass
- Flouride is put in toothpaste
- Chlorine is used to clean water as it kills most bacteria
- Group 7
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