C10 Flashcards
What is the trend in atomic radius going down group 7?
Increases as each atom will have more inner shells, therefore more shielding, therefore weaker efa between outer shell and nucleus, therefore less able to be pulled in
What is the trend in reactivity down the group 7?
Decreases as group 7 elements need to gain an electron. Therefore since as you go down the group, each atom will have more inner shells, therefore the efa between each nucleus and its outer electron will weaken, therefore as you go down the group it becomes harder to attract an electron.
What is the trend in first ionisation energy down the group?
Decrease as when you go down the group, each atom will gain an inner shell, therefore the efa between the nucleus and outer shell will decrease, meaning it will require less energy to remove the outer electron as it is less attracted to the nucleus.
What is the trend in m.p/b.p down the group?
It will increase. This is because the group 7 are simple molecules that contain vdw forces between their molecules. Therefore as you go down the group, the Ar of each molecule will increase, therefore it will have more electrons and thus stronger vdw forces.
What is the trend in oxidising power (ability to be an oxidising agent) down the group?
Decreases down the group as their ability to attract electrons decreases as they have a greater atomic radius, therefore have more inner shells and shielding weaking the efa between the outer shell and nucleus.
What do halides to other halides in a reaction?
A halide will displace any other halide that is beneath it in the periodic table.
What is the trend in the reducing power of the halide ion?
Increases down the group, because the atomic radius increases meaning more inner shells and more shielding, weakening the efa between the nucleus and outer shell, meaning it will become easier to lose an electron
Redox Reaction with Fluorine:
NaF + H2SO4 ——> NaHSO4 + HF
Redox Reaction with Chlorine:
NaCl + H2SO4 ——> NaHSO4 + HCL
Redox Reactions with Bromine:
NaBr + H2SO4 ——> NaHSO4 +HBr
2HBr + H2SO4 —–> Br2 + SO2 + 2H2O
Redox Reaction with Iodine:
NaI + H2SO4 —> NaHSO4 + HI
2HI + H2SO4 —> I2 + SO2 +2H20
6HI + SO2 —> H2S + 3I2 + 2H2O
What does HBr, HI, HF and HCl produce?
Steamy fumes
What is NaI?
A black solid
What observation is linked to H2S?
Bad egg smell
What observation is linked to SO2?
Colourless gas
What is silver ions in an aqueous solution used for?
Used to react with a metal halide to form a precipitate in a silver halide. This does not work for fluorine as it is soluble in water.
How to identify metal halides with silver ions?
Dilute nitric acid is added to remove any carbonate ions or hydroxide ions. This has to be done as they would interfere by forming an insoluble silver carbonate or silver hydroxide. After a few drops of silver nitrate solution is added to form the halide precipitate.
What colour is AgCl precipitate when Cl- reacts with Ag+?
White Precipitate
What colour is AgBr precipitate when Br- reacts with Ag+?
Cream Precipitate
What colour is AgI precipitate when I- reacts with Ag+?
Yellow precipitate
What happens when AgCl precipitate is added to dilute NH3?
The white precipitate will dissolve
What happens when the AgBr precipitate is added to dilute NH3?
Nothing
What happens when AgI precipitate is added to dilute NH3
Nothing
What happens when the AgCl precipitate is added to conc NH3?
The white precipitate dissolves
What happens when the AgBr precipitate is added to conc NH3
The cream precipitate dissolves
What happens when the AgI precipitate is added to conc NH3
Nothing
What is formed in the reaction of Chlorine and cold water?
Chlorate (I) ions (ClO-) and Chloride ions
What is the balanced symbol reaction for chlorine and cold water?
Cl2 + H2O —–> ClO- + Cl- + 2H+
What type of reaction is chlorine plus cold water?
Disproportionation reaction. Chlorine is both reduced and oxidised
What is formed in the reaction of Chlorine and cold water in the presence of UV light?
4HCl + O2
What is the balanced symbol reaction for the reaction of chlorine and cold water in the presence of UV light.
(UV)
2Cl2 + 2H20 —-> 4HCl + O2
What is a use of chlorine?
Chlorine is used in small quantities to kill bacteria in water treatment processes.
What is a safety precaution when using chlorine?
Use in small quantities, use a fume cupboard etc.
What is formed in the reaction of chlorine and sodium hydroxide?
NaClO + NaCl + H2O (NaClO is the key ingredient in bleach)
What is the balanced symbol reaction for the reaction between sodium hydroxide and chlorine?
NaOH + Cl2 —> NaClO + NaCl + H2O
What is the test for hydroxide ions?
Turns red litmus paper blue
What is the test for carbonate ion?
When an acid is added, it will fizz and give off a CO2 gas. This can be collected and bubbled through limewater which will turn cloudy if the gas is CO2.
Colour of I2 gas?
Purple
Colour of HI?
Black solid
Colour of Br2 gas?
Brown/Orange
