AQA A-Level Chemistry (new spec)
2.3 Group 7 - The Halogens
What are the 5 halogens? - Correct Answers-Fluorine, Chlorine, Bromine, Iodine & Astatine
Why isn't astatine studied? - Correct Answers-Because it's very radioactive and can't exist for
more than a few seconds before decaying.
What oxidation state are the G7 elements usually found in? - Correct Answers--1, found as X-1
ions (known as halide ions)
Appearance of G7 elements: Fluorine - Correct Answers-Very pale yellow gas, highly reactive
Appearance of G7 elements: Chlorine - Correct Answers-Pale green gas, poisonous in high
concentrations
Appearance of G7 elements: Bromine - Correct Answers-Red liquid, gives off dense brown or
orange poisonous fumes
Appearance of G7 elements: Iodine - Correct Answers-Shiny grey solid that sublimes to a purple
gas
Appearance of G7 elements: Astatine - Correct Answers-Black solid, is radioactive
Trends of G7: Boiling point as you go down the group - Correct Answers-Increases
-Number of VDW forces increase between molecules as they're larger
-More energy is needed to break the bonds
Trends of G7: Electronegativity - Correct Answers-Decreases
-Atomic radius increases
-Shielding increases
-Less attraction between the outer electrons and the protons in the nucleus
Are the halogens oxidising or reducing agents? - Correct Answers-Oxidising
-They can accept electrons and are reduced
F2(g) + 2e- --> 2F-(aq)
Cl2(g) + 2e- --> 2Cl-(aq)
, Br2(l) + 2e- --> 2Br-(aq)
I2(aq) + 2e- --> 2I-(aq)
Trends of G7: Oxidising power - Correct Answers-Decrease
-Atoms become larger
-Shielding increases
-Outer e-'s are less attracted to the nucleus
Are halides oxidising or reducing agents? - Correct Answers-Reducing
-They can lose electrons and can get oxidised
2F-(aq) --> F2(g) + 2e-
2Cl-(aq) --> Cl2(g) + 2e-
2Br-(aq) --> Br2(l) + 2e-
2I-(aq) --> I2(aq) + 2e-
Trends of G7: Reducing power - Correct Answers-Increase
-Atoms larger
-Shielding increases
-Electrons aren't attracted to the nucleus as strongly so they're more easily lost
Trends of G7: Displacement reactions - Correct Answers-The more reactive halogens (strongest
oxidising agents) will displace the more reactive halides (strongest reducing agents) from
solutions of their ions
What happens when: potassium chloride reacts with chlorine? - Correct Answers-No reaction
What happens when: potassium chloride reacts with bromine? - Correct Answers-No reaction
What happens when: potassium chloride reacts with iodine? - Correct Answers-No reaction
What happens when: potassium bromide reacts with chlorine? - Correct Answers-A yellow
solution is formed, Cl has displaced Br.
Cl2(aq) + 2Br-(aq) --> 2Cl-(aq) + Br2(aq)
What happens when: potassium bromide reacts with bromine? - Correct Answers-No reaction
What happens when: potassium bromide reacts with iodine? - Correct Answers-No reaction
What happens when: potassium iodide reacts with chlorine? - Correct Answers-A brown
solution is formed, Cl has displaced I
2.3 Group 7 - The Halogens
What are the 5 halogens? - Correct Answers-Fluorine, Chlorine, Bromine, Iodine & Astatine
Why isn't astatine studied? - Correct Answers-Because it's very radioactive and can't exist for
more than a few seconds before decaying.
What oxidation state are the G7 elements usually found in? - Correct Answers--1, found as X-1
ions (known as halide ions)
Appearance of G7 elements: Fluorine - Correct Answers-Very pale yellow gas, highly reactive
Appearance of G7 elements: Chlorine - Correct Answers-Pale green gas, poisonous in high
concentrations
Appearance of G7 elements: Bromine - Correct Answers-Red liquid, gives off dense brown or
orange poisonous fumes
Appearance of G7 elements: Iodine - Correct Answers-Shiny grey solid that sublimes to a purple
gas
Appearance of G7 elements: Astatine - Correct Answers-Black solid, is radioactive
Trends of G7: Boiling point as you go down the group - Correct Answers-Increases
-Number of VDW forces increase between molecules as they're larger
-More energy is needed to break the bonds
Trends of G7: Electronegativity - Correct Answers-Decreases
-Atomic radius increases
-Shielding increases
-Less attraction between the outer electrons and the protons in the nucleus
Are the halogens oxidising or reducing agents? - Correct Answers-Oxidising
-They can accept electrons and are reduced
F2(g) + 2e- --> 2F-(aq)
Cl2(g) + 2e- --> 2Cl-(aq)
, Br2(l) + 2e- --> 2Br-(aq)
I2(aq) + 2e- --> 2I-(aq)
Trends of G7: Oxidising power - Correct Answers-Decrease
-Atoms become larger
-Shielding increases
-Outer e-'s are less attracted to the nucleus
Are halides oxidising or reducing agents? - Correct Answers-Reducing
-They can lose electrons and can get oxidised
2F-(aq) --> F2(g) + 2e-
2Cl-(aq) --> Cl2(g) + 2e-
2Br-(aq) --> Br2(l) + 2e-
2I-(aq) --> I2(aq) + 2e-
Trends of G7: Reducing power - Correct Answers-Increase
-Atoms larger
-Shielding increases
-Electrons aren't attracted to the nucleus as strongly so they're more easily lost
Trends of G7: Displacement reactions - Correct Answers-The more reactive halogens (strongest
oxidising agents) will displace the more reactive halides (strongest reducing agents) from
solutions of their ions
What happens when: potassium chloride reacts with chlorine? - Correct Answers-No reaction
What happens when: potassium chloride reacts with bromine? - Correct Answers-No reaction
What happens when: potassium chloride reacts with iodine? - Correct Answers-No reaction
What happens when: potassium bromide reacts with chlorine? - Correct Answers-A yellow
solution is formed, Cl has displaced Br.
Cl2(aq) + 2Br-(aq) --> 2Cl-(aq) + Br2(aq)
What happens when: potassium bromide reacts with bromine? - Correct Answers-No reaction
What happens when: potassium bromide reacts with iodine? - Correct Answers-No reaction
What happens when: potassium iodide reacts with chlorine? - Correct Answers-A brown
solution is formed, Cl has displaced I
