1. Group 2 and 7 revision

2. For each of the 11 statements name the substance
An insoluble group 2 sulphate
A silver halide that forms an insoluble cream precipitate on reaction with dilute ammonia solution. This then dissolves in concentrated ammonia.
An insoluble group 2 hydroxide
A white coloured silver halide
A gas that forms hypochlorite (HClO) and HCl when bubbled through water.
A substance that will form an orange liquid when it reacts with bromide
A group 1 carbonate that does NOT decompose on heating
An ion that reacts with sulphuric acid to produce a purple solid
A brown toxic acidic gas
An ion that reacts with sulphuric acid to produce an orange liquid
Magnesium reacts with hot water to make

3. For each of the 11 statements name the substance
BaSO4
An insoluble group 2 sulphate
A silver halide that forms an insoluble cream precipitate on reaction with dilute ammonia solution. This then dissolves in concentrated ammonia.
AgBr
Mg(OH)2
An insoluble group 2 hydroxide
AgCl
Cl2
A white coloured silver halide
A gas that forms hypochlorite (HClO) and HCl when bubbled through water. F2
Cl2
Li2CO3
A substance that will form an orange liquid when it reacts with bromide
A group 1 carbonate that does NOT decompose on heating I-
NO2
An ion that reacts with sulphuric acid to produce a purple solid
A brown toxic acidic gas
Br-
MgO
An ion that reacts with sulphuric acid to produce an orange liquid
Magnesium reacts with hot water to make

4. Unit 2 – Group 2/7 elements RevisionB4
Mid
End C
Can I describe the trends in reactivity for the group 2 and group 7 elements?
Can I explain these trends using keywords? A
Can I solve independently group 2 and 7 reactivity problems using ionic equations? B
Do not just do ticks and crosses – traffic lights – put a picture of traffic lights on the PPT

5. Write balanced ionic equations with state symbols for the reactions that happen. Explain why they happen. F2
Cl- F2 I-
Cl-
Br2
Br2 I-

6. Write balanced ionic equations with state symbols for the reactions that happen. Explain why they happen. F2
Cl- F-
Cl2 2 2 g aq aq g F2 I- F- I2 2 2 g aq aq s
Cl-
Br2
Br2
Br- I- I2 2 2 l aq aq s

7. Simple answer: a more reactive halogen displaces another less reactive halogen in an ionic compound.F2
Cl- F2 I-
Cl-
Br2
Br2 I-

8. Unit 2 – Group 2/7 elements RevisionB4
Mid
End C
Can I describe the trends in reactivity for the group 2 and group 7 elements?
Can I explain these trends using keywords? A
Can I solve independently group 2 and 7 reactivity problems using ionic equations? B
Do not just do ticks and crosses – traffic lights – put a picture of traffic lights on the PPT

9. Write down a description and explanation for two of these trends
Melting point going down group 2
Reactivity going down group 2
Boiling point going down group 7
Oxidising power of group 7 halogen ATOMS or MOLECULES
Reducing power of group 7 ANIONS (challenge question)

10. Write down a description and explanation for two of these trends
Melting point going down group 2
Decreases owing to larger ionic radius and lower charge density on cation. Therefore the attraction between the cation and the sea of delocalised electrons is weaker

11. Write down a description and explanation for two of these trends
Reactivity going down group 2
Increases as the metal is easier to oxidise. This is because the attraction between the nucleus and the outershell electron is weaker owing to more electron shielding and an increased atomic radius

12. On a post it note write down a description and explanation for two of these trends
Boiling point going down group 7
Increases as there are more electrons. Therefore there is an increase in the London force (induced dipole) between molecules.

13. Write down a description and explanation for two of these trends
Reducing power of group 7 ANIONS
Increases as there is weaker attraction between the nucleus and the outermost electron gets weaker and so the outermost electron is more readily given to another species, thereby reducing it.

14. Write down a description and explanation for two of these trends
Oxidising power of group 7 halogen ATOMS or MOLECULES
Decreases because the electronegativity decreases going down group 7 from F to I

15. Unit 2 – Group 2/7 elements RevisionB4
Mid
End C
Can I describe the trends in reactivity for the group 2 and group 7 elements?
Can I explain these trends using keywords? A
Can I solve independently group 2 and 7 reactivity problems using ionic equations? B
Do not just do ticks and crosses – traffic lights – put a picture of traffic lights on the PPT

16. A* A B
A student wants to make magnesium oxide. Explain using a symbol equation how this can be done using magnesium and water.
A scientist has prepared a white coloured silver halide. Identify the halide ion.
Explain using symbol equations how a solution of sodium chlorate (I) can be prepared.
Explain using oxidation numbers and symbol equations that the iodide ion has greater reducing power than bromide and chloride
A chemist wants to make a solution of hypochlorite (HOCl) to disinfect swimming pool. He has chloride ions, fluorine and water. Explain using 2 symbol equations how she could do this. You do not need to explain how any of the substances need to be separated. A

17. A B A* A Mark scheme H2O (g) + Mg (s)  MgO (s) + H2 (g) 2. chloride
NaOH (aq) + Cl2 (g)  NaClO3 (aq) + NaCl (aq) + H2O (l) COLD
4. H2SO4 + NaCl  HCl + NaHSO4 --- S goes from +6 to +6
H2SO4 + HBr  Br2 + SO2 + H2O --- S goes from +6 to +4
H2SO4 + HI  I2 + H2S + H2O ---- S goes from +6 to -2
Therefore I- is the strongest reducing agent because sulphur has become more negative in oxidation number.
5. F2 (g) + Cl-(aq)  F- (aq) + Cl2 (g)
H2O(l) + Cl2 (g)  HClO (aq) + HCl (aq)
Mark scheme A