Covalent Bonding (Edexcel GCSE Chemistry)

Exam Questions

3 hours32 questions
1a1 mark

This question is about the structure and bonding in methane. 

 A molecule of methane is shown in Figure 1. 

Figure 1
 
methane-ch4


Give the formula of this methane molecule. 

1b1 mark

What type of bonding is found in methane? 

Tick (one box. 

 Ionic  
 Covalent  
 Metallic   
1c2 marks

The bonding in methane can be shown using a dot and cross diagram. 

Carbon has four electrons in its outer shell, and hydrogen has one. 

Complete the dot and cross diagram for methane.

aqa-gcse-2-1e-tp2c-methane-dot-and-cross-diagram
1d1 mark

Oxygen is in Group 6 of the Periodic Table.

Complete the dot and cross diagram to show how electrons are shared in water.

Some of them have been done for you.

aqa-gcse-2-1e-tp3e-water-dot-and-cross-diagram

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2a2 marks

A chlorine molecule consists of two chlorine atoms and is an example of a simple molecule consisting of two atoms.

Which of the following statements is correct 

Tick () two boxes.

A chlorine molecule has the formula Cl2  
Chlorine is bonded metallically   
Atoms are typically 0.1 nanometers in size   
Chlorine is a solid at room temperature   
2b2 marks

Figure 1 shows two chlorine atoms which each have seven electrons in their outermost shells.

Draw a diagram to show how two atoms of chlorine bond to form a chlorine molecule. You only need to show outer electrons.

Use Figure 1 to help you.

1-4-covalent-bonding-2b-a

Figure 1

2c1 mark

Hydrogen gas has the same type of bonding as chlorine.

Why is hydrogen a gas at room temperature?

Tick ( ) one box

The intermolecular forces are strong  
The bonding in hydrogen is weak   
The intermolecular forces are weak   
2d1 mark

What is the correct electronic configuration of chlorine? 

  A 2.7
  B 2.8.7
  C 2.8.8.7
  D 2.7.8

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3a1 mark

This question is all about covalent bonds.

Which of these oxides contains covalent bonds?

A

Aluminium oxide

B

Carbon dioxide

C

Sodium oxide

D

Lead oxide 

3b1 mark

Water is also an oxide.

Figure 1 is a dot and cross diagram to show the bonding in a water molecule.

edx-1-4e-paper-1-q3b-water-dot-cross-diagramFigure 1

 State the formula of water.

3c2 marks

Give the number of:

i)
Bonding electrons in the outer shell of the oxygen atom.

[1]

ii)
Non-bonding electrons in the outer shell of the oxygen atom.

[1]

3d2 marks

Is this statement true or false:

‘When water boils the covalent bond between the atoms is broken.’

Give a reason for your answer.

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4a1 mark

Figure 1 shows the electronic configuration of a hydrogen atom.

edx-1-4e-paper-1-q4a-hydrogen-atom-diagram

Figure 1

Complete Figure 2 to show the electronic configuration of a chlorine atom.

edx-1-4e-paper-1-q4a-chlorine-atom-diagram

Figure 2

4b2 marks

Atoms achieve a stable electronic configuration when their outer shell is full.

i)
State how many electrons a hydrogen atom needs in order to have a full outer shell.

[1]

ii)
State how many electrons a chlorine atom needs in order to have a full outer shell.

[1]

4c1 mark

Hydrogen and chlorine react to form a covalent bond.

Describe what happens when a covalent bond is formed between a hydrogen and chlorine atom.

4d1 mark

What is formed when a hydrogen and chlorine atom join?

A

A hydrogen chloride atom

B

A hydrogen chlorine molecule

C

A hydrogen chloride atom

D

A hydrogen chloride molecule 

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5a1 mark

This question is all about the size of atoms.

Put these structures in order of size starting with the smallest.

Oxygen atom, oxygen nucleus, oxygen molecule, proton

5b1 mark

What is the size of a typical atom?

A

0.1 nm

B

0.1 μm

C

0.1 mm

D

0.1 cm

5c3 marks

Fluorine and chlorine are both in Group 7 of the Periodic Table.

State which has the smaller atoms.

Explain why, in terms of electronic configuration

5d1 mark

What instrument allows scientists to see individual atoms?

A

Electron microscope

B

Light microscope

C

Oscilloscope

D

Telescope

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11 mark

Ammonia, NH3, is a small covalent molecule.

How many non-bonding, outer-shell electrons are present in one molecule of ammonia?

  A 0
  B 2
  C 5
  D 6

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2a3 marks

Covalent substances can be simple molecular covalent or giant covalent.

i)
Ammonia is a simple molecular, covalent substance.
Which is the most likely set of properties for ammonia?
(1)
 
      melting point
in °C
boiling point
in °C
ability to conduct
electricity in liquid state
  A 1713 2950 does not conduct
  B −78 −33 does not conduct
  C −39 357 conducts
  D 801 1413 conducts

 

ii)
Ammonia, NH3, is made by reacting nitrogen with hydrogen.
Write the balanced equation for this reaction.
(2)
2b2 marks

Oxygen, O2, is also a simple molecular, covalent substance.

Draw a dot and cross diagram for the molecule of oxygen.

2c6 marks

Figure 8 shows the arrangement of carbon atoms in diamond, graphene and a fullerene (C60).

fig-8-q8c-1cho-1h-paper-1-june-2018
Figure 8

Consider these three substances.

Explain, in terms of their structures and bonding, their relative melting points, strengths and abilities to conduct electricity.

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31 mark

Which statement is not true about covalent bonding? 

  A Two atoms share at least one pair of electrons between them
  B Covalent bonding can result in small molecules being formed
  C Covalent bonds are weaker than ionic bonds
  D Covalent bonding occurs to allow atoms to have stable, full outer shells of electrons

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41 mark

What are the typical sizes, in orders of magnitude, of atoms and small molecules? 

      Size of atoms and small molecules / m
  A x 10-8
  B x 10-9
  C   x 10-10
  D   x 10-11

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5a2 marks

Iodine and bromine are both halogens. The bonding in iodine is similar to the bonding in bromine.

Suggest two reasons why they bond in similar ways.

5b2 marks

Complete the diagram below to show the bonding arrangement in a molecule of iodine.

Show the outer shell electrons only.

iodine-electron-configuration-blank

5c2 marks

Explain why liquid iodine is unable to conduct electricity.

5d4 marks

Iodine has an atomic number of 53 and xenon has an atomic number of 54. Explain why xenon exists as an atom where as iodine exists as a molecule.

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1a1 mark

This question is about covalent bonding.

What is a covalent bond? 

1b1 mark

Complete the dot and cross diagram in Figure 1 to show the bonding in propane. 

aqa-gcse-2-1h-tq-3b-propane-dot-and-cross-diagram
Figure 1
1c2 marks

Explain why propane cannot conduct electricity. 

1d2 marks

Carbon dioxide, CO2, bonds in a similar way to propane. Complete Figure 2 to show the bonding.

1-4-covalent-bonding-1d
Figure 2

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2a1 mark

A hydrogen atom is 0.074 nm, or 0.00000000074 m long.

Write 0.00000000074 m in standard form.

2b1 mark

Caesium atoms are 0.267 nm long.

State how many orders of magnitude exist between the length of a hydrogen atom and the length of a caesium atom.

2c2 marks

Hydrogen exists as molecules.

Draw a dot-cross diagram for a hydrogen molecule.

2d2 marks

Hydrogen molecules are the smallest molecules.

Explain why.

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3a1 mark

Figure 1 shows a dot-cross diagram and structure of a methane molecule.

 edx-1-4h-paper-1-q3a-methane-diagrams

                                             Dot-cross diagram                                                                      Structure

Figure 1

Name the type of bond formed when two atoms share a pair of electrons.

3b2 marks

Complete Figure 2 to show the dot cross diagram of a carbon dioxide molecule.

edx-1-4h-paper-1-q3b-carbon-dioxide-diagram

Figure 2

3c1 mark

Draw the structure of a carbon dioxide molecule.

3d4 marks

The boiling point of methane is -162°C.
The boiling point of carbon dioxide is -75°C.

A student concludes that this difference is due to the number of bonds between the atoms in each molecule.

Discuss if you think this conclusion is correct.

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4a3 marks

An ethene molecule contains carbon and hydrogen atoms.
Its formula is C2H4.

Complete the dot and cross diagram of ethene, shown in Figure 1.

edx-1-4h-paper-1-q4a-ethene-dot-cross-diagram

Figure 1

4b1 mark

Complete Figure 2 to show the structure of ethene.

Use a single line to show each covalent bond.

edx-1-4h-paper-1-q4b-ethene-diagram

Figure 2

4c1 mark

Give an advantage of using Figure 1 rather than Figure 2 to represent ethene.

4d2 marks

Higher Tier Only

Table 1 shows the bond energies for a single and double carbon bond.

Table 1

Bond

Bond energy (kJ/mol)

C-C

347

C=C

611

Describe and explain the difference between the bond energies.

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5a1 mark

A nitrogen molecule has the formula N2.

Nitrogen molecules are diatomic.
Suggest what this means.

5b2 marks

Nitrogen atoms have the electronic configuration 2.8.5.

Draw a dot and cross diagram to show the covalent bonding in a nitrogen molecule.

Show only the electrons in the outer shell.

5c2 marks

Use your knowledge of bonding to explain why nitrogen is a gas at room temperature.

5d3 marks

Nitrogen is an unreactive gas.

Suggest why.

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