Edexcel GCSE Chemistry: Combined Science

Topic Questions

GCSEChemistry: Combined ScienceEdexcelTopic Questions5. Groups in the Periodic Table5.1 Group 1

5.1 Group 1

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1a8 marks

The first four elements in group 1 are lithium, sodium, potassium and rubidium.

Rubidium reacts with water to form rubidium hydroxide and hydrogen.

2Rb(s) + 2H2O(l) → 2RbOH(aq) + H2(g)

i)
Predict what you would see when a small piece of rubidium is placed in a large volume of water.
(3)
ii)
Why is rubidium more reactive than potassium?
(1)
  ☐ A the metallic bonds in rubidium are weaker than those in potassium
  ☐ B rubidium is a softer metal than potassium 
  ☐ C the outer electron of a rubidium atom is further from the nucleus than potassium’s 
  ☐ D rubidium has a more exothermic reaction with water than potassium does

iii)
8.5 g of rubidium are reacted completely with water.

The reaction makes a solution of rubidium hydroxide.
The volume of this solution is 2.5 dm3.

Calculate the concentration of the rubidium hydroxide solution in gdm-3.
(relative atomic mass: Rb = 85; relative formula mass: RbOH = 102)
(4)
concentration = .............................................................. gdm-3

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1b3 marks

An example of an endothermic reaction is the reaction between rubidium hydroxide and ammonium carbonate, (NH4)2CO3.
This reaction forms rubidium carbonate, Rb2CO3, ammonia and one other product.

Write the balanced equation for this reaction.

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2a1 mark

The elements in Group 1 become more reactive as you go down the group. 

Potassium is below sodium in Group 1. 

Both metals are added to water. 

Predict one observation you would see that shows potassium is more reactive than sodium.

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2b3 marks

Write the balanced symbol equation for the reaction between potassium and water. 

You should include state symbols in your answer. 

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2c3 marks

Explain why potassium is more reactive than sodium. 

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2d2 marks

Potassium reacts with oxygen to form potassium oxide. 

Explain why potassium oxide has a high melting point. 

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3a1 mark

Group 1 metals are located in the Periodic Table. 

Explain why they are called the alkali metals. 

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3b4 marks

Sodium hydroxide is produced when sodium is added to water. 

Sodium hydroxide reacts with sulfuric acid in a neutralisation reaction. 

i)
Write the balanced symbol equation for this reaction. 
(2)
ii)
Write the ionic equation for this reaction. 
(2)

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3c1 mark

Suggest why sodium needs to be stored under oil. 

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3d2 marks

Sodium is a Group 1 metal. 

Sodium is able to conduct electricity. 

Explain why. 

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4a4 marks

Element Z has the following properties:

  • It is a solid at room temperature
  • Does not conduct heat or electricity
  • Forms simple molecules with non-metals
  • Forms giant ionic lattices with metals in which it has a 1- ion

Select the formula of the compound formed when element Z reacts with calcium from the list below.

CaO CaCl2 CaI2 CaS CaBr



Explain your answer using the information provided.

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4b5 marks

Calcium is a Group 2 metal. Group 2 metals show similar trends in reactivity to Group 1 metals as you go down the group. 

Magnesium is another Group 2 metal.

Explain why, in terms of atomic structure, magnesium reacts in a similar way to calcium with element Z but it is less reactive than calcium.

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11 mark

Which statement explains why Group 1 metals get more reactive further down the group?
 

  ☐ A There is an increasing attraction between the outer electron and nucleus
  ☐ B There is less shielding of the outer electron so it is easier to lose
  ☐ C There is a decreasing attraction between the outer electron and nucleus so the electron is more easily lost
  ☐ D The outer electron is closer to the nucleus and harder to lose 

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2a
Sme Calculator3 marks

Lithium, sodium and potassium are reactive metals in group 1 of the periodic table.

Sodium metal tarnishes in air to form a layer of sodium oxide on its surface.
0.92 g of sodium combined with 0.32 g of oxygen in this oxide.

Calculate the empirical formula of this sodium oxide.
(relative atomic masses: O = 16, Na = 23)

You must show your working.

empirical formula of sodium oxide = ...................................

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2b3 marks
Sodium reacts with water to form sodium hydroxide in solution and hydrogen.

Complete the balancing of the equation for this reaction and add the state symbols for each substance.

............Na (............) + 2H2O (............) rightwards arrow ............NaOH (............) + H2 (............)

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2c7 marks

In an experiment equal-sized pieces of lithium, sodium and potassium are added to separate samples of water.

i)
A flame is produced only with potassium because potassium
(1)
  ☐ A is the softest metal
  ☐ B has the lowest melting point
  ☐ C is the most reactive
  ☐ D is the only flammable metal

ii)
A teacher demonstrated this experiment.

The results are shown in Figure 14.

  lithium sodium potassium
position of metal in water floats floats floats
movement of metal slow fast very fast
effervescence / bubbling slow fast very fast

Figure 14

Describe, in detail, how the teacher would demonstrate this experiment safely, showing how the results give the order of reactivity of the metals.

(6)

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2d2 marks

Explain, in terms of electronic configurations, the increase in reactivity from lithium to sodium to potassium.

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31 mark

Sodium reacts with water to form sodium hydroxide solution and hydrogen. 

Which of the following balanced symbol equations with state symbols is correct? 
 

  ☐ A 2Na (s) + H2O (l)  →  2NaOH (aq) + H2 (g) 
  ☐ B 2Na (s) + 2H2O (l)  →  2NaOH (l) + H2 (g) 
  ☐ C 2Na (s) + 2H2O (l)  →  2NaOH (aq) + H2 (g) 
  ☐ D Na (s) + 2H2O (l)  →  NaOH (aq) + 2H2 (g) 

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41 mark

Which of the following is not a property of Group 1 metals?

 
  ☐ A They are are soft 
  ☐ B They have relatively high melting points 
  ☐ C They are very reactive 
  ☐ D They have relatively low densities 

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5a1 mark

Some of the elements in the periodic table are metals.
The electronic configuration of a metal is 2.8.3


Which row shows the group and period of the periodic table where this metal is found?

      group period
  ☐ A 2 3
  ☐ B 2 8
  ☐ C 3 2
  ☐ D 3  3

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5b5 marks
Lithium, potassium and rubidium are alkali metals.

i)
Describe what you would see when a small piece of rubidium is dropped on to water.

(2)

ii)
The electronic configuration of lithium is 2.1
The electronic configuration of potassium is 2.8.8.1
Lithium is less reactive than potassium.

Explain, in terms of their electronic configurations, why lithium is less reactive than potassium.

(3)

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5c
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Higher Only

Lithium has two naturally occurring isotopes, lithium-6 and lithium-7.

 

A sample of lithium contains

7.59% of lithium-6
92.41% of lithium-7.


Calculate the relative atomic mass of lithium in this sample.

Give your answer to two decimal places.
You must show your working.

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61 mark

When lithium is added to water, a gas is produced. 

Which test and result would correctly identify this gas?

 
  ☐ A A glowing splint will relight 
  ☐ B Limewater will turn cloudy 
  ☐ C Litmus paper will bleach white
  ☐ D A burning splint will give a squeaky pop sound

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71 mark

When sodium reacts with water an alkaline solution is formed.

Which statement about why this happens is true?

 
  ☐ A It contains an ionic compound
  ☐ B It contains hydroxide ions
  ☐ C It contains water
  ☐ D Hydrogen gas is made 

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