Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
321–330 of 423 · Normal
Question 321
6 marks · Normal
Answer and see the solution →This question tests your understanding of covalent bonding and how it affects the properties of substances.
(a)[2 marks]Calculate the total number of covalent bonds formed in a molecule of ethene (C2H4). Show your working.
(b)[4 marks]The table shows the electrical conductivity of three substances:
Substance Electrical conductivity Diamond Does not conduct Graphite Conducts C60 fullerene Does not conduct Explain, using their structure and bonding, why graphite conducts electricity but diamond and C60 fullerene do not.
Question 322
6 marks · Normal
Answer and see the solution →This question is about using dot-and-cross diagrams to interpret structures and properties.
(a)[2 marks]Draw a dot-and-cross diagram for a molecule of nitrogen, N2, showing only the outer shell electrons.
(b)[2 marks]Explain why nitrogen gas contains molecules, not a giant covalent structure like diamond and graphite.
(c)[2 marks]Explain why simple covalent molecules like N2 have much lower melting points than giant covalent structures such as diamond.
Question 323
2 marks · Normal
Answer and see the solution →Potassium is a metal.
Draw a labelled diagram to show the arrangement of particles in a metallic lattice of potassium. You may use dots or circles to represent positive ions and crosses or small circles to represent delocalised electrons.
Question 324
4 marks · Normal
Answer and see the solution →Read the statements about metallic bonding and answer the questions.
(a)[1 mark]State what holds the particles together in a metallic lattice.
(b)[1 mark]Describe what is meant by the term 'delocalised electrons'.
(c)[2 marks]Explain why positively charged ions do not move apart in a metal.
Question 325
3 marks · Normal
Answer and see the solution →The melting point of magnesium (Group 2) is much higher than that of sodium (Group 1).
Using information about metallic bonding, calculate the number of delocalised electrons contributed per atom in each metal, and explain how this relates to their melting points.
Question 326
3 marks · Normal
Answer and see the solution →A student tries to represent a metallic lattice using the following statement:
'A metal is made up of separate molecules containing metal atoms.'
Does this statement accurately describe a metallic lattice? Give reasons for your answer, and describe the actual arrangement of particles in a metallic lattice.
Question 327
4 marks · Normal
Answer and see the solution →The table below shows data for three metals.
Properties of three metals Metal Ion formed Number of delocalised electrons per atom Melting point (°C) Sodium Na+ 1 98 Magnesium Mg2+ 2 650 Aluminium Al3+ 3 660 Use the data to answer the questions.
(a)[1 mark]For sodium, write the charge on the ion and state how many delocalised electrons each atom provides.
(b)[2 marks]Explain, using the table, why magnesium has a much higher melting point than sodium.
(c)[1 mark]Suggest, using the data, why aluminium and magnesium have similar melting points despite aluminium having a higher ion charge.
Question 328
1 mark · Normal
Answer and check →Which property of metals is directly explained by the presence of delocalised electrons in their structure?
- A.High density
- B.Shiny appearance
- C.Electrical conductivity
- D.High boiling point
Question 329
2 marks · Normal
Answer and see the solution →Calcium metal has a giant structure.
Draw and clearly label a simple 2D diagram to show the arrangement of ions and delocalised electrons in calcium metal.
Question 330
4 marks · Normal
Answer and see the solution →Read the paragraph and answer the questions.
Solid metals consist of positive metal ions in a sea of delocalised electrons. The bonding involves the electrostatic attraction between the ions and the electrons.
(a)[1 mark]Define metallic bonding.
(b)[1 mark]State what particles are involved in metallic bonding.
(c)[2 marks]Explain how metallic bonding holds the metal together.