Inorganic I- Group 7 the halogens Flashcards
What is the trend in atomic radius down group 7?
It increases due to additional electron shells.
What is the trend in reactivity down group 7?
Reactivity decreases as atomic radius and shielding increases.
What is the trend in ionisation energy down group 7?
Ionisation energy decreases down the group due to increased atomic radius and shielding.
What is the trend in boiling point down group 7?
It increases as van der waals forces increase down the group.
What is the trend in oxidising power down group 7?
The halogens act as good oxidising agents. The oxidising power decreases down the group.
How does the trend in oxidising power affect displacement in group 7?
Cl2 will displace Br- and Cl- ions.
Br2 will displace I- ions.
I2 won’t displace any halide ions.
What is the trend in the reducing power of halides?
The reducing power increases down the group due to increased shielding and atomic radius.
What are the redox reactions of H2SO4 and flouride and chloride ions?
NaF + H2SO4 → NaHSO4 + HF
NaCl + H2SO4 → NaHSO4 + HCl
What are the redox reactions of H2SO4 and bromide ions?
NaBr + H2SO4 → NaHSO4 + HBr
2HBr + H2SO4 → Br2 + SO2 + 2H2O
What are the redox reactions of H2SO4 and iodide ions?
NaI + H2SO4 → NaHSO4 + HI
2HI + H2SO4 → I2 + SO2 + 2H2O
6HI + SO2 → H2S + 3I2 + 2H2O
What happens when AgNO3 is in the presence of Cl- ions?
A white precipitate forms (AgCl).
What happens when AgNO3 is in the presence of Br- ions?
A cream precipitate forms (AgBr)
What happens when AgNO3 is in the presence of I- ions?
A yellow precipitate forms (AgI)
How can the precipitates formed in the test for halide ions be further distinguished?
AgCl dissolves when dilute and concentrated NH3 is added.
AgBr dissolves when concentrated NH3 is added.
AgI does not dissolve.
What is the equation for the reaction between chlorine and cold water?
Cl2 + H2O → ClO- + Cl- + 2H+
What is the reaction between chlorine and cold water an example of?
Disproportionation, as chlorine is both oxidised and reduced.
What is the equation for the reaction between chlorine and water in the presence of UV light?
2Cl2 + H2O → 4HCl + O2
What is a use for chlorine?
Chlorine is used in small quantities to kill bacteria. This poses some risks as chlorine is toxic. However, the benefits of clean water outweigh that risk.
What is the equation for the reaction of chlorine with cold aqueous sodium hydroxide?
2NaOH + Cl2 → NaClO + NaCl + H2O
What is sodium hypochlorite used for?
To produce bleach.
What is the test for sulphate ions?
Addition of BaCl2, forming a white precipitate.
What is the test for hydroxide ions?
Can be identified with red litmus, which turns blue, as the OH- ions make the solution alkaline.
What is the test for carbonate ions?
When an acid such as HCl is added effervesence will be produced and CO2 will be released. This gas can be collected and bubbled through limewater which will turn cloudy, confirming it as carbon dioxide.
What is the colour of the flame produced with calcium?
Brick red
