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CAIE A Level Chemistry 9701

Chemical bonding questions

Exam-style questions on Chemical bonding, ordered from foundation to challenge. Pick one, write your answer the way you would in the exam, and it comes back marked against the mark scheme, point by point.

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Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.

  1. Explain4 marksStandardAluminium is a typical metal. Explain, in terms of the particles involved, how metallic bonding holds a piece of aluminium metal together.
  2. Compare5 marksStandardIn a piece of solid zinc, each atom releases two electrons into a shared sea of delocalised electrons; in solid sodium, each atom releases one electron. The ionic radius of ceZn^2+ is 0.074 nm and that of Na+ is 0.102…
  3. Explain4 marksStandardThe density of ice is approximately 0.92 g cm⁻³, while the density of liquid water at 4°C is 1.00 g cm⁻³. Explain this difference in terms of the hydrogen bonding in water.
  4. Compare5 marksStandardCompare the shapes and bond angles of ammonia, NH3, and water, H2O. Use VSEPR theory to explain the reason for any difference in bond angle.
  5. Explain4 marksStandardThe Pauling electronegativity values for sulfur and chlorine are 2.58 and 3.16 respectively. Explain the difference in electronegativity between these two elements. Use these values to predict the type of bonding in…
  6. Describe5 marksStandardSulfur hexafluoride, SF6, is a covalent molecule in which a sulfur atom is bonded to six fluorine atoms. Describe the covalent bonding in SF6, and explain why sulfur is able to form six covalent bonds even though a…
  7. Explain4 marksStandardMagnesium oxide (MgO) has a melting point of 2852 °C, while sodium chloride (NaCl) has a melting point of 801 °C. Explain, in terms of the ionic bonding present, why the melting point of magnesium oxide is much higher…
  8. Compare5 marksStandardMagnesium oxide, MgO, and calcium fluoride, CaF2, are both ionic compounds. Compare the ionic bonding in the two compounds, referring to the ions present and to the relative strength of the bonding.
  9. Compare5 marksStandardThe Pauling electronegativities of oxygen, fluorine and chlorine are 3.5, 4.0 and 3.0, respectively. Compare the electronegativity of fluorine with those of oxygen and chlorine, and explain why fluorine is the most…
  10. Explain4 marksStandardWater has a relatively high boiling point and its solid form, ice, is less dense than the liquid. Explain both of these properties in terms of hydrogen bonding between H2O molecules.
  11. Compare5 marksStandardThe Pauling electronegativity values for the elements of Period 3 and Group 2 are shown below. Period 3: Na 0.9, Mg 1.2, Al 1.5, Si 1.8, P 2.1, S 2.5, Cl 3.0 Group 2: Be 1.5, Mg 1.2, Ca 1.0, Sr 0.9, Ba 0.8 Compare the…
  12. Compare5 marksStandardCompare the bonding in the ammonia molecule, NH3, and the ammonium ion, NH4+, with reference to their dot-and-cross diagrams. In your answer, describe the number of bonding pairs and lone pairs on the central nitrogen…
  13. Compare5 marksStandardEthanol, C2H5OH, boils at 78 °C; propane, C3H8, boils at -42 °C. Compare the types and relative strengths of the intermolecular forces acting between the molecules in each liquid. In your answer, state the atoms…
  14. Describe5 marksStandardCopper is used for electrical wiring. Describe the metallic bonding in solid copper, and how this bonding allows copper wire to conduct electricity.
  15. Explain4 marksStandardExplain, using VSEPR theory, why the H-O-H bond angle in H2O is 104.5°, whereas the H-C-H bond angle in CH4 is 109.5°.
  16. Compare5 marksStandardCompare the carbon-carbon bond in ethane, C2H6, with the carbon-carbon bond in ethene, C2H4. In your answer, refer to the types of covalent bonds present, the bond lengths, and the relative reactivity of the two…
  17. Explain4 marksStandardSodium chloride (NaCl), magnesium oxide (MgO) and calcium fluoride (CaF2) are ionic compounds. Explain what is meant by ionic bonding. For each compound, state the ions present and describe how these ions are formed…
  18. Compare5 marksStandardSodium chloride and magnesium oxide are both ionic compounds. Compare the properties of sodium chloride and magnesium oxide, explaining any differences in terms of the ionic bonding present.
  19. Describe5 marksStandardA student fills a sealed glass bottle to the brim with liquid water, caps it and places it in a freezer. The bottle cracks as the water freezes. Using your knowledge of hydrogen bonding between water molecules…
  20. Compare5 marksStandardCompare the types of intermolecular forces present in H2O and H2S. Use your answer to explain why H2O has a significantly higher boiling point than H2S.
  21. Explain4 marksStandardExplain, in terms of orbital overlap and bond types, why the bond between the two nitrogen atoms in N2 is stronger and shorter than the bond between the two nitrogen atoms in N2H4.
  22. Describe5 marksStandardThe ammonium ion, NH4+, forms when NH3 accepts a proton. Describe the shape of, and bond angle in, the NH4+ ion and explain, using VSEPR theory, why the ion has this shape.
  23. Explain4 marksStandardExplain, using VSEPR theory, the shapes and bond angles of the ammonia molecule, NH3, and the water molecule, H2O.
  24. Compare5 marksStandardTable 1 gives data for the carbon-carbon bonds in ethane, C2H6, and ethene, C2H4. Molecule Carbon-carbon bond Bond length / pm Bond energy / kJ mol^-1 C2H6 C-C 154 348 C2H4 C=C 134 612 Compare the nature of the…
  25. Describe5 marksStandardDescribe ionic bonding. In your answer, refer to the formation of sodium chloride, magnesium oxide and calcium fluoride.
  26. Explain4 marksStandardThe Pauling electronegativity of chlorine is 3.0 and that of iodine is 2.5. A student suggests that iodine should be more electronegative than chlorine because iodine has more protons. Explain why the student is…
  27. Suggest4 marksStandardTwo oxygen atoms in a molecule of O2 are joined by a covalent bond. A student draws a dot-and-cross diagram of O2, using dots for the outer-shell electrons of one atom and crosses for the outer-shell electrons of the…
  28. Explain4 marksStandardThe ammonium ion, NH4+, contains both covalent and coordinate (dative covalent) bonds. Explain how dot-and-cross diagrams can be used to represent the bonding in NH4+. In your answer, describe the electron arrangements…
  29. Describe5 marksStandardThe Pauling electronegativities of the elements from sodium to chlorine in Period 3 are as follows: Na 0.9, Mg 1.2, Al 1.5, Si 1.8, P 2.1, S 2.5, Cl 3.0. Describe the trend in electronegativity across this period and…
  30. Explain4 marksStandardAmmonia gas reacts with hydrogen chloride gas to form solid ammonium chloride. The ammonium ion, NH4+, contains a coordinate (dative covalent) bond. Explain, in terms of electrons and orbitals, how this coordinate bond…
  31. Compare5 marksStandardThe hydroxonium ion, H3O+, forms when a hydrogen ion, H+, bonds to a water molecule, H2O. Compare the bond formed between the oxygen atom and the added H+ with the two O-H covalent bonds already present in the water…
  32. Suggest6 marksChallengeEthene, C2H4, rapidly decolourises bromine water, whereas ethane, C2H6, does not react with bromine water under the same conditions. The carbon-carbon bond energy of ethene is 612 kJ mol⁻¹, but that of ethane is only…
  33. Suggest6 marksChallengeSodium chloride and magnesium oxide are both ionic compounds. (a) Suggest, in terms of the ions present and the electrostatic attraction between them, why the ionic bond in magnesium oxide is stronger than the ionic…
  34. Compare7 marksChallengeSodium chloride, NaCl, and magnesium oxide, MgO, are both ionic compounds. The melting point of NaCl is about 800 °C, while that of MgO is about 2800 °C. Compare the ionic bonding in these two compounds, including what…
  35. Suggest6 marksChallengeThe Pauling electronegativities of the halogens are given. element electronegativity F 4.0 Cl 3.0 Br 2.8 I 2.5 (a) Suggest why electronegativity decreases from fluorine to iodine. (b) The electronegativity of fluorine…
  36. Describe7 marksChallengeAmmonium chloride, NH4Cl, contains ionic, covalent and coordinate bonding. Describe the dot-and-cross diagrams for the NH4+ ion and the Cl- ion, and explain how these diagrams illustrate the types of bonding present.
  37. Describe7 marksChallengeDescribe the intermolecular forces present in liquid ammonia (NH3) and liquid water (H2O). In your answer, explain how bond polarity arises from electronegativity differences, and use your description to account for…
  38. Suggest6 marksChallengeA student claims that a dot-and-cross diagram of methane, CH4, shows that in any molecule every atom must have eight electrons in its outer shell. Suggest how you would use dot-and-cross diagrams of methane, CH4…
  39. Compare7 marksChallengeWater, H2O, boils at 373 K. Hydrogen sulfide, H2S, the analogous compound of sulfur, boils at 213 K. Compare the types of intermolecular force present in water with those present in hydrogen sulfide. Use your…
  40. Describe7 marksChallengeThe Pauling electronegativities of two elements, A and B, are 0.9 and 3.0, respectively. (a) Define the term electronegativity. (b) Describe the factors that influence the electronegativity of an element. Explain the…
  41. Compare7 marksChallengeSteel wire can be bent round a post without breaking, and it conducts electricity even while it is bent. Compare the explanations of these two properties in terms of metallic bonding.
  42. Describe7 marksChallengeDescribe the bonding in the aluminium chloride dimer, Al2Cl6. In your answer, you should: identify the types of covalent bonds present, including any dative covalent bonds explain the hybridisation of the aluminium…
  43. Describe7 marksChallengeDescribe the shapes and bond angles of the following molecules and ions, explaining your answers using VSEPR theory. (a) BeCl2 (b) SO3 (c) H3O+ (d) SF6
  44. Suggest6 marksChallengeAluminium foil is produced by repeatedly hammering and rolling aluminium into very thin sheets. Suggest, in terms of the metallic bonding in aluminium, why aluminium can be deformed in this way without breaking apart.
  45. Compare7 marksChallengeThe Pauling electronegativities of sodium, magnesium and potassium are 0.9, 1.2 and 0.8, respectively. Compare the electronegativity of Na with that of Mg, and the electronegativity of Na with that of K. For each pair…
  46. Suggest6 marksChallengeWater has a much higher surface tension than propane, C3H8, at the same temperature. Ice floats on liquid water. Suggest explanations for both of these properties, in terms of the intermolecular forces between the…