Halogens
- Created by: Chloe Trotter
- Created on: 22-04-16 14:35
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- Halogens
- Trend in melting/boiling points
- Gas, gas, liquid, solid
- Increases as you go down the group
- As you go down the group the atomic radius increases
- Each extra shell contains more electrons
- Larger van der waals forces
- Needs more energy to break
- Increases as you go down the group
- As you go down the group the atomic radius increases
- Each extra shell contains more electrons
- Larger van der waals forces
- Needs more energy to break
- Needs more energy to break
- Larger van der waals forces
- Each extra shell contains more electrons
- As you go down the group the atomic radius increases
- Increases as you go down the group
- Needs more energy to break
- Larger van der waals forces
- Each extra shell contains more electrons
- As you go down the group the atomic radius increases
- Trend in electronegativity
- The relative tendency of an atom to attract electrons in a covalent bond
- Decreases down the group
- Atomic radius increases
- Nucleus is less able to attract a bonding pair of electrons
- Atomic radius increases
- Displacement reactions
- Between halide ions and halogens
- Oxidising strength decreases down the group
- Electron accepters that are themselves reduced
- A halogen that has strong oxidising strength will displace a halogen with less oxidisation strength
- Chlorine will displace both bromide and iodide ions
- Very pale green solution turns yellow in the presence of Bromide ions
- Very pale green solution turns brown in the presence of iodide ions
- Bromine will displace iodide ions
- Yellow solution turns brown with iodide ions present
- Iodine won't displace anything
- Solution stays brown
- Chlorine will displace both bromide and iodide ions
- Reactions of halide ions with silver nitrate
- Used to identify which halide ion is present
- 1) Add Nitric acid
- Reacts any carbonates to prevent formation of AgCO3
- This would mask the desires observations
- Reacts any carbonates to prevent formation of AgCO3
- 2) Add silver nitrate in drops
- Fluoride won't form a precipitate
- Chloride will form a white precipitate
- Bromide will form a cream precipitate
- Iodide will form a pale yellow precipitate
- 3) Add ammonia solution
- This is done because it is hard to tell the difference between white cream and pale yellow
- Dilute ammonia dissolves silver chloride precipitate
- Concentrated ammonia dissolves silver bromide precipitate
- Silver iodide won't dissolve
- Reaction of halide salts with concentrated sulphuric acid
- Reducing power increases down the group
- A reducing agent donates electrons
- Because atomic radius increases down the group
- Outer electrons are easier to give away as the nucleus has less of a pull on them
- Fluride and Chloride aren't strong enough reducing agent's to reduce S in H2SO4
- Mean's only acid base reactions occur
- No redox reactions
- Gives off white steamy fumes
- Mean's only acid base reactions occur
- Bromide has an inital acid based reaction and then a redox
- Reduces the sulphur in H2SO4 from +6 to +4 in SO2
- Iodide is the strongest reducing agent
- Reduces sulphur from +6 to +4 in SO2
- Then reduces it to O in S and -2 in H2S
- Bad egg smell
- Reduces sulphur from +6 to +4 in SO2
- Reducing power increases down the group
- Disproportionation reactions of chlorine and chlorate(l)
- A reaction where an element simultaneously oxidises and reduces
- Chlorine with water
- Chlorine is both reducing and oxidising
- Add a universal indicator and it will first turn red due to acidity
- It will then turn colourless as HClO bleaches the colour
- Add a universal indicator and it will first turn red due to acidity
- Chlorine is both reducing and oxidising
- Chlorine with water in sunlight has a different reaction
- Will react the same up until equilibrium
- Greenish colour of chlorine fades as Cl2 reacts to form O2
- Will react the same up until equilibrium
- Chlorine is used to treat drinking water and swimming pools
- It kills bacteria
- It's health benefits outweigh it's toxic effects
- Reactions of chlorine with cold/dilute sodium hydroxide
- Chlorine and bromine/iodine will react with cold sodium hydroxide
- NaOH
- The colour of the halogen will fade to colourless
- Mixture of NaCl and NaClO are used in bleach
- Also kills bacteria and disinfects
- Chlorine and bromine/iodine will react with cold sodium hydroxide
- Trend in melting/boiling points
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