Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Explaining the increase in reactivity
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →Lithium (Li), sodium (Na), and potassium (K) are all Group 1 metals. Each loses its single outer electron in reactions. The number of protons in lithium is 3, in sodium is 11, and in potassium is 19.
Calculate the number of electron shells in an atom of potassium and explain how this relates to its reactivity compared to sodium.
Question 12
3 marks · Normal
Answer and see the solution →When potassium and sodium are each added separately to water, potassium reacts much more vigorously than sodium.
Use knowledge of their atomic structures to explain fully why potassium is more reactive than sodium.
Question 13
4 marks · Normal
Answer and see the solution →The table shows the number of electron shells and the speed of reaction with water for the three Group 1 metals:
Metal Number of electron shells Relative speed of reaction (1=slow, 3=fast) Lithium 2 1 Sodium 3 2 Potassium 4 3 (a)[1 mark]Describe the pattern shown between number of electron shells and speed of reaction.
(b)[2 marks]Suggest how the electronic configuration of rubidium (Rb), the next Group 1 metal, might affect its reaction with water.
(c)[1 mark]State what you would expect the relative speed of rubidium's reaction with water to be compared to potassium.
Question 14
1 mark · Normal
Answer and check →Why does the reactivity of Group 1 elements increase as you go down the group?
- A.The outer electron becomes harder to lose because it is closer to the nucleus.
- B.More electron shells mean the outer electron is further from the nucleus and lost more easily.
- C.The atoms gain more protons so become less reactive.
- D.Atoms of Group 1 elements get lighter down the group.
Question 15
2 marks · Normal
Answer and see the solution →Explain why lithium reacts more slowly than sodium when added to water.
Question 16
4 marks · Normal
Answer and see the solution →Group 1 metals lose their outer electron in chemical reactions.
(a)[2 marks]Describe the difference in atomic structure between sodium and potassium.
(b)[2 marks]Explain how this difference affects their reactivity.
Question 17
2 marks · Hard
Answer and see the solution →Explain, in terms of their electronic configurations, why a rubidium atom loses its outer electron more easily than a sodium atom.
Question 18
5 marks · Hard
Answer and see the solution →(a)[1 mark]State the electronic configuration of a potassium atom.
(b)[2 marks]Using the electronic configurations, compare the positions of the outer electrons in sodium and potassium atoms.
(c)[2 marks]Explain, with reference to their atomic structure, why potassium reacts more vigorously with water than sodium does.
Question 19
2 marks · Hard
Answer and see the solution →Why is the outer electron in a caesium atom less strongly attracted to the nucleus than in a lithium atom? Give two reasons.