Edexcel GCSE Chemistry: Groups and Reactivity

The alkali metals in Group 1 (lithium, sodium and potassium) all react with water to form a metal hydroxide and hydrogen gas. As you go down Group 1, the metals become more reactive.

Using lithium, sodium and potassium as examples, describe the trend in reactivity down Group 1 and explain this trend in terms of electronic structure. (6 marks)

Transition metals (such as iron, copper and manganese) have different properties from the Group 1 metals.

(a) Give two physical properties of transition metals that are different from those of Group 1 metals. (2 marks)

(b) Many transition metals can form ions with different charges. Iron forms both $Fe^{2+}$Fe2+ and $Fe^{3+}$Fe3+ ions. State the chemical name of the compound $Fe_2O_3$Fe2​O3​, using the correct Roman numeral. (2 marks)

Chlorine, bromine and iodine are halogens in Group 7. A more reactive halogen can displace a less reactive halogen from a solution of its salt.

Chlorine water (colourless) was added to a colourless solution of potassium bromide. The mixture turned orange.

(a) Write a balanced symbol equation for the reaction between chlorine and potassium bromide ($KBr$KBr). (2 marks)

(b) Explain why the mixture turned orange. (1 mark)

The table shows the results when four different metals (W, X, Y and Z) were added to solutions of the salts of the other metals. A tick (✓) means a displacement reaction happened; a cross (✗) means no reaction.

Metal added ↓ / Salt solution →	W salt	X salt	Y salt	Z salt
W	—	✗	✗	✗
X	✓	—	✗	✗
Y	✓	✓	—	✗
Z	✓	✓	✓	—

(a) Use the results to place the four metals in order of reactivity, from most reactive to least reactive. (2 marks)

(b) Explain how the results for metal Z show that it is the most reactive. (1 mark)

Iron is extracted from iron oxide in a blast furnace by heating it with carbon. One reaction that takes place is:

$2Fe_2O_3 + 3C \rightarrow 4Fe + 3CO_2$2Fe2​O3​+3C→4Fe+3CO2​

Explain, in terms of oxygen, why the iron oxide has been reduced and the carbon has been oxidised in this reaction. (2 marks)

A flame test can be used to identify the metal ion in a compound. A sample of a compound was held in a blue Bunsen flame and produced a lilac flame colour.

Name the metal ion present in the compound. (1 mark)