Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Rubidium and caesium
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →A student is given the information below about the reactions of three Group 1 metals with water:
Metal Time taken to disappear in water (s) Lithium 45 Sodium 35 Potassium 18 Calculate the average decrease in time taken to disappear from lithium to potassium per step down the group.
Question 12
3 marks · Normal
Answer and see the solution →Explain, in terms of atomic structure, why potassium is more reactive than lithium.
Question 13
4 marks · Normal
Answer and see the solution →The table below shows times taken for different alkali metals to disappear when added to water:
Time taken to disappear in water Metal Time (s) Lithium 50 Sodium 30 Potassium 11 (a)[1 mark]State the relationship between the metal and the time taken to disappear in water.
(b)[2 marks]Which metal is the most reactive? Explain how the data supports your answer.
(c)[1 mark]Rubidium is below potassium in Group 1. Predict what you would expect to observe if rubidium was added to water.
Question 14
1 mark · Normal
Answer and check →Which statement best explains the trend in reactivity of Group 1 metals as you go down the group?
- A.The outer electron is closer to the nucleus and more difficult to remove.
- B.Metals lower in the group have smaller atoms.
- C.The outer electron is further from the nucleus and less strongly attracted.
- D.The number of protons decreases down the group.
Question 15
2 marks · Normal
Answer and see the solution →Lithium, sodium, and potassium all react with water. State the name and a property of the gas produced in each reaction.
Question 16
4 marks · Normal
Answer and see the solution →(a)[1 mark]Write a balanced chemical equation for the reaction of potassium with water.
(b)[2 marks]Describe what you would observe when a small piece of sodium is placed in water.
(c)[1 mark]Suggest one safety precaution that should be taken when carrying out this reaction.
Question 17
2 marks · Hard
Answer and see the solution →State two observations you would expect when a piece of sodium is added to water. Explain how these observations differ from the reaction of potassium with water.
Question 18
5 marks · Hard
Answer and see the solution →The table below shows some properties of Group 1 metals at room temperature.
Metal Melting Point (°C) Lithium 181 Sodium 98 Potassium 64 Rubidium 39 Caesium 29 (a)[1 mark]Describe the trend in melting point as you go down Group 1 from lithium to caesium.
(b)[1 mark]Predict the appearance (physical state and colour) of caesium at room temperature.
(c)[3 marks]Explain, in terms of atomic structure, the trend in reactivity from lithium to caesium.
Question 19
2 marks · Hard
Answer and see the solution →Describe the appearance of lithium and potassium at room temperature. State one difference you would notice between them by observation.