Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AQA A-Level Chemistry > 2.3 Group 7 > Flashcards

2.3 Group 7 Flashcards

1
Q

Trend in atomic radius down group 7

A

Increases
- Main shells and shielding increases
- Weaker nuclear attraction to the outer electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is the radius of halide ions greater than halogen atoms?

A
  • Ions have more electrons
  • Same number of protons
  • Weaker nuclear attraction in ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Trend in boiling point down group 7

A

Increases (halogens become less volatile)
- Larger molecules, more electrons
- Stronger van der Waals forces
- More energy needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Trend in electronegativity down group 7

A

Decreases
- More main shells and shielding
- Less attraction between shared pair and nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Trend in first ionisation energy down group 7

A

Decreases
- More main shells and shielding
- Less nuclear attraction to outer electron
- Less energy needed to remove it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Colour of chlorine

A

Green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Colour of bromine

A

Red-brown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Colour of Iodine

A

Black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

State of chlorine (at room temperature)

A

Gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

State of bromine (at room temperature)

A

Liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Colour of chlorine in aqueous solution

A

Pale green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Colour of bromine in aqueous solution

A

Orange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Colour of iodine in aqueous solution

A

Brown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Colour of chlorine in cyclohexane

A

Pale green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Colour of bromine in cyclohexane

A

Orange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Colour of iodine in cyclohexane

A

Pink-purple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the best solvents for halogens?

A

Non-polar solvents like cyclohexane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Trend in solubility down group 7

A

Solubility decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Are halogens oxidising agents or reducing agents?

A

Oxidising agents (they accept electrons to form halide ions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Trend in oxidising power down group 7

A

Decreases
- More main shells and shielding
- Less nuclear attraction to electron being accepted
- Less ability to gain electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Disproportionation

A

A redox reaction in which the same element is both oxidised and reduced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is formed when chlorine reacts with water?

A

HCl + HClO (HClO decomposes in sunlight to form HCl and O₂)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

HClO

A

Chloric (I) acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Colour change with litmus paper/universal indicator: HClO

A

Indicator is bleached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Benefits and risks of using Cl₂ in water treatment
Benefit: Kills bacteria at non-toxic levels Risk: Toxic in larger quantities
26
How are sodium chloride, sodium chlorate(1) and water produced from Cl₂?
Reacting Cl₂ with cold dilute sodium hydroxide solution
27
Uses of NaCl + NaClO + H₂O solution
- As a bleach - To kill bacteria
28
Test for halide ions
- Make a solution of the test substance - Add dilute nitric acid (to remove other ions) - Add silver nitrate solution
29
Positive test for Cl⁻
White precipitate forms (AgCl)
30
Positive test for Br⁻
Cream precipitate forms (AgBr)
31
Positive test for I⁻
Yellow precipitate forms (AgI)
32
Why do F⁻ ions not form a precipitate with silver nitrate?
AgF is soluble in water
33
Adding dilute ammonia solution to precipitate of AgCl
AgCl dissolves forming colourless solution
34
Adding dilute ammonia solution to precipitate of AgBr
AgBr is insoluble - cream solid remains
35
Adding dilute ammonia solution to precipitate of AgI
AgI is insoluble - yellow solid remains
36
Adding conc. ammonia solution to precipitate of AgCl
AgCl dissolves forming a colourless solution
37
Adding conc. ammonia solution to precipitate of AgBr
AgBr dissolves forming a colourless solution
38
Adding conc. ammonia solution to precipitate of AgI
AgI is insoluble - yellow solid remains
39
Test for a reducing agent (gasses)
Orange acidified potassium dichromate paper turns green
40
Halides are ________ agents
Reducing They lose electrons to form halogens
41
____________ sulfuric acid reacts with _____ halide salts
Concentrated, solid
42
H₂SO₄ Oxidation number of S
+6 Sulfuric (VI) acid
43
SO₂ Oxidation number of S
+4 Sulfur (IV) oxide / Sulfur dioxide
44
S Oxidation number
0
45
H₂S Oxidation number of S
-2 Hydrogen sulfide
46
Two reactions when a solid halide salt reacts with conc. sulfuric acid
**1. Acid-base** (H₂SO₄ acts as acid) **2. Redox** (H₂SO₄ acts as an oxidising agent)
47
Why does NaCl + H₂SO₄ not have a reduction or oxidation product?
Cl⁻ is not a strong enough reducing agent
48
Products of NaCl + H₂SO₄
- Acid-base: HCl + NaHSO₄
49
Products of NaBr + H₂SO₄
- Acid-base: HBr + NaHSO₄ - Oxidation: Br₂ - Reduction: SO₂
50
Products of NaI + HSO₄
- Acid-base: HI + H₂SO₄ - Oxidation: I₂ - Reduction: SO₂ + S + H₂S
51
**Halide redox reactions** Appearance/test for: HI / HBr / HCl gasses
Steamy white fumes
52
**Halide redox reactions** Appearance/test for: Br₂
Orange fumes
53
**Halide redox reactions** Appearance/test for: I₂
Black solid/purple vapour
54
**Halide redox reactions** Appearance/test for: SO₂
- Colourless gas with a choking odor - Orange acidified potassium dichromate paper turns green
55
**Halide redox reactions** Appearance/test for: S
Yellow solid
56
**Halide redox reactions** Appearance/test for: H₂S
- Colourless gas - Lead ethanoate paper, white → black
57
Why does KI + H₂SO₄ have multiple reduction products?
I⁻ ions are very good reducing agents so they can reduce H₂SO₄ to its lowest oxidation number (as well as all the stages in between)
58
Why do halide ions act as reducing agents?
They lose electrons to form halogens
59
Trend in reducing power of the halides down group 7
Increases - More main shells and shielding - Nuclear attraction to outer electron decreases - Electron is more easily lost
60
Strongest group 7 oxidising agent
F₂
61
Strongest group 7 reducing agent
I⁻
62
What kind of reaction is chlorine + water?
Reverseable

AQA A-Level Chemistry (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions