IGCSE · Chemistry 0620 · The Periodic Table

Group I: IGCSE Chemistry questions with answers

Free Group I questions for IGCSE Chemistry (0620), part of The Periodic Table. Each question has the answer and the marking points an examiner would look for.

Generate a full Group I worksheet →All The Periodic Table questions

Group I practice questions

Question 1Multiple choice · 1 markA* challenge

Caesium is below potassium in Group I.
Which prediction is correct?

  1. A It has a lower melting point than potassium.
  2. B It is less reactive than potassium.
  3. C It does not react with water.
  4. D It is harder than lithium.
Show answer

Answer: A

Question 2Multiple choice · 1 mark

How does the density of Group I metals change down the group?

  1. A It decreases then increases.
  2. B It generally increases.
  3. C It decreases.
  4. D It stays the same.
Show answer

Answer: B

Question 3Multiple choice · 1 mark

Which statement describes alkali metals?

  1. A The Group I metals, which react with cold water to form an alkaline hydroxide and hydrogen
  2. B A cell that uses hydrogen and oxygen to produce electricity, with water as the only product
  3. C A reaction in which the products can react to re-form the original reactants
  4. D Protecting iron by attaching a more reactive metal, such as zinc, which corrodes instead
Show answer

Answer: A

Question 4Structured · 7 marksA* challenge

Lithium, sodium and potassium are in Group I.

(a)

Describe what is seen when sodium is added to water.

[3]
(b)

Write a balanced equation for the reaction of potassium with water.

[2]
(c)

Explain why potassium is more reactive than sodium.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)floats, moves, fizzes, melts into ball
Any 3 of: floats; moves around on the surface; fizzes/bubbles; melts into a ball (dissolves) B3
3
(b)2K + 2H₂O → 2KOH + H₂
correct formulae B1
balanced B1
2
(c)outer electron further from nucleus, more easily lost
the outer electron is further from the nucleus/more shielded B1
so it is lost more easily B1
2
Question 5Structured · 3 marks

Lithium is stored under oil.

(a)

Describe how the surface of freshly cut lithium changes in air.

[1]
(b)

Write a word equation for the reaction of lithium with oxygen.

[1]
(c)

Describe the trend in reactivity of Group I metals with water.

[1]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)shiny then tarnishes
it is shiny but quickly tarnishes/becomes dull B1
1
(b)lithium + oxygen → lithium oxide
lithium + oxygen → lithium oxide B1
1
(c)increases down group
reactivity increases down the group B1
1
Question 6Structured · 4 marks

The Group I metals show trends in their properties.

(a)

Describe the trend in melting point down the group.

[1]
(b)

Predict two properties of rubidium.

[2]
(c)

Explain why Group I metals are stored under oil.

[1]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)decreases
the melting point decreases B1
1
(b)soft; reacts violently with water; low melting point
Any 2 of: any two: soft; low melting point (below K); reacts very vigorously/explosively with water; forms RbOH B2
2
(c)react with air and water
to stop them reacting with oxygen and water vapour in the air B1
1

More The Periodic Table questions

Arrangement of elementsGroup VIITransition elementsNoble gases

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Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in