4.6 Past Paper Questions

1. What is the formula for the compound formed by Calcium and Nitrogen?

A. CaN

B. Ca₂N

C. Ca₂N₃

D. Ca₃N₂

(Total 1 mark)

2. Element X is in group 2, and element Y in group 7, of the periodic table. Which ions will be present in the compound formed when X and Y react together?

A. X⁺ and Y^–

B. X ²⁺ and Y^–

C. X⁺ and Y ^2–

D. X ^2– and Y⁺

(Total 1 mark)

3. Based on electronegativity values, which bond is the most polar?

A. B―C

B. C―O

C. N―O

D. O―F

(Total 1 mark)

4. What is the Lewis (electron dot) structure for Sulphur Dioxide?

(Total 1 mark)

5. Which substance is most soluble in water (in mol dm^–3) at 298 K?

A. CH₃CH₃

B. CH₃OCH₃

C. CH₃CH₂OH

D. CH₃CH₂CH₂CH₂OH

(Total 1 mark)

6. According to VSEPR theory, repulsion between electron pairs in a valence shell decreases in the order

A. lone pair-lone pair > lone pair-bond pair > bond pair-bond pair.

B. bond pair-bond pair > lone pair-bond pair > lone pair-lone pair.

C. lone pair-lone pair > bond pair-bond pair > bond pair-lone pair.

D. bond pair-bond pair > lone pair-lone pair > lone pair-bond pair.

(Total 1 mark)

7. Which molecule is linear?

A. SO₂

B. CO₂

C. H₂S

D. Cl₂O

(Total 1 mark)

8. Why is the boiling point of PH₃ lower than that of NH3?

A. PH₃ is non-polar whereas NH₃ is polar.

B. PH₃ is not hydrogen bonded whereas NH₃ is hydrogen bonded.

C. Van der Waals’ forces are weaker in PH₃ than in NH₃.

D. The molar mass of PH₃ is greater than that of NH₃.

(Total 1 mark)

9. Which molecule is non-polar?

A. H₂CO

B. SO₃

C. NF₃

D. CHCl₃

(Total 1 mark)

10. What happens when sodium and oxygen combine together?

A. Each sodium atom gains one electron.

B. Each sodium atom loses one electron.

C. Each oxygen atom gains one electron.

D. Each oxygen atom loses one electron.

(Total 1 mark)

11. Which statement is correct about two elements whose atoms form a covalent bond with each other?

A. The elements are metals.

B. The elements are non-metals.

C. The elements have very low electronegativity values.

D. The elements have very different electronegativity values.

(Total 1 mark)

12. Which substance has the lowest electrical conductivity?

A. Cu_(s)

B. Hg_(l)

C. H_2(g)

D. LiOH_(aq)

(Total 1 mark)

13. When the following bond types are listed in decreasing order of strength (strongest first), what is the correct order?

A. covalent > hydrogen > van der Waals’

B. covalent > van der Waals’ > hydrogen

C. hydrogen > covalent > van der Waals’

D. van der Waals’ > hydrogen > covalent

(Total 1 mark)

14. Which statement is true for most ionic compounds?

A. They contain elements of similar electronegativity.

B. They conduct electricity in the solid state.

C. They are coloured.

D. They have high melting and boiling points.

(Total 1 mark)

15. What is the valence shell electron pair repulsion (VSEPR) theory used to predict?

A. The energy levels in an atom

B. The shapes of molecules and ions

C. The electronegativities of elements

D. The type of bonding in compounds

(Total 1 mark)

16. Which fluoride is the most ionic?

A. NaF

B. CsF

C. MgF₂

D. BaF₂

(Total 1 mark)

17. Which substance is most similar in shape to NH3?

A. GaI₃

B. BF₃

C. FeCl₃

D. PBr₃

(Total 1 mark)

18. Which statement is a correct description of electron loss in this reaction?

2Al + 3S --> Al₂S₃

A. Each Aluminium atom loses two electrons.

B. Each Aluminium atom loses three electrons.

C. Each Sulphur atom loses two electrons.

D. Each Sulphur atom loses three electrons.

(Total 1 mark)

19. Which molecule has the smallest bond angle?

A. CO₂

B. NH₃

C. CH₄

D. C₂H₄

(Total 1 mark)

20. In which substance is hydrogen bonding present?

A. CH₄

B. CH₂F₂

C. CH₂CHO

D. CH₃OH

(Total 1 mark)

21. Which is a correct description of metallic bonding?

A. Positively charged metal ions are attracted to negatively charged ions.

B. Negatively charged metal ions are attracted to positively charged metal ions.

C. Positively charged metal ions are attracted to delocalised electrons.

D. Negatively charged metal ions are attracted to delocalised electrons.

(Total 1 mark)

22. What intermolecular forces are present in gaseous hydrogen?

A. Hydrogen bonds

B. Covalent bonds

C. Dipole-dipole attractions

D. Van der Waals’ forces

(Total 1 mark)

23. Which molecule is polar?

A. CO₂

B. PF₃

C. CH₄

D. BF₃

(Total 1 mark)

24. What are responsible for the high electrical conductivity of metals?

A. Delocalised positive ions

B. Delocalised valence electrons

C. Delocalised atoms

D. Delocalised negative ions

(Total 1 mark)

25. Which compound has the least covalent character?

A. SiO₂

B. Na₂O

C. MgCl₂

D. CsF

(Total 1 mark)

26. When C₂H₄, C₂H₂and C₂H₆ are arranged in order of increasing C–C bond length, what is the correct order?

A. C₂H₆ , C₂H₂, C₂H₄

B. C₂H₄, C₂H₂, C₂H₆

C. C₂H₂, C₂H₄, C₂H₆

D. C₂H₄, C₂H₆ , C₂H₂

(Total 1 mark)

27. Which compound contains both ionic and covalent bonds?

A. MgCl₂

B. HCl

C. H₂CO

D. NH₄Cl

(Total 1 mark)

28. When the species BF₂⁺, BF₃ and BF₄^– are arranged in order of increasing F−B−F bond angle, what is the correct order?

A. BF₃, BF₄^–, BF₂⁺

B. BF₄^–, BF₃, BF₂⁺

C. BF₂⁺, BF₄^–, BF₃

D. BF₂⁺, BF3, BF₄^–

(Total 1 mark)

29. Which species has a trigonal planar shape?

A. CO₃^2–

B. SO₃^2–

C. NF₃

D. PCl₃

30. When C₂H₄, C₂H₂and C₂H₆are arranged in order of increasing C–C bond length, what is the correct order?

A. C₂H₆, C₂H₂, C₂H₄

B. C₂H₄, C₂H₂, C₂H₆

C. C₂H₂, C₂H₄, C₂H₆

D. C₂H₄, C₂H₆, C₂H₂

(Total 1 mark)

31. What is the formula for an ionic compound formed between an element, X, from Group 2 and an element, Y, from group 6?

A. XY

B. X₂Y

C. XY₂

D. X₂Y₆

(Total 1 mark)

32. In the molecules N₂H₄, N₂H₂, and N₂, the nitrogen atoms are linked by single, double and triple bonds, respectively. When these molecules are arranged in increasing order of the lengths of their nitrogen to nitrogen bonds (shortest bond first) which order is correct?

A. N₂H₄, N₂, N₂H₂

B. N₂H₄, N₂H₂, N₂

C. N₂H₂, N₂, N₂H₄

D. N₂, N₂H₂, N₂H₄

(Total 1 mark)

33. The compounds listed have very similar molar masses. Which has the strongest intermolecular forces?

A. CH₃CHO

B. CH₃CH₂OH

C. CH₃CH₂F

D. CH₃CH₂CH₃

(Total 1 mark)

34. What is the shape of the CO₃^2– ion and the approximate O–C–O bond angle?

A. Linear, 180°

B. Trigonal planar, 90°

C. Trigonal planar, 120°

D. Pyramidal, 109°

(Total 1 mark)

35. Which combination of Enthalpy change of vaporization and boiling point is the result of strong intermolecular forces?

(Total 1 mark)

36. What is the formula of the compound formed when Aluminium reacts with Oxygen?

A. Al₃O₂

B. Al2O₃

C. AlO₂

D. AlO₃

(Total 1 mark)

37. Which statement is true for compounds containing only covalent bonds?

A. They are held together by electrostatic forces of attraction between oppositely charged ions.

B. They are made up of metal elements only.

C. They are made up of a metal from the far left of the periodic table and a non-metal from the far right of the periodic table.

D. They are made up of non-metal elements only.

(Total 1 mark)

38. How many electrons are used in the carbon-carbon bond in C₂H₂?

A. 4

B. 6

C. 10

D. 12

(Total 1 mark)

39. Which compound has the highest boiling point?

A. CH₃CH₂CH₃

B. CH₃CH₂OH

C. CH₃OCH₃

D. CH₃CHO

(Total 1 mark)

40. What type of solid materials are typically hard, have high melting points and poor electrical conductivities?

I. Ionic

II. Metallic

III. Covalent-network

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

(Total 1 mark)

41. The boiling points of the Hydrides of the Group 6 elements are shown below.

(i) Explain the trend in boiling points from H₂S to H₂Te.

……………………………………………………………………………………….

(2)

(ii) Explain why the boiling point of water is higher than would be expected from the group trend.

……………………………………………………………………………………….

(2)

(Total 4 marks)

42. (i) State the shape of the electron distribution around the Oxygen atom in the water molecule and state the shape of the molecule.

………………………………………………………………………………………

(2)

(ii) State and explain the value of the HOH bond angle.

………………………………………………………………………………………

(2)

(Total 4 marks)

43. Explain why the bonds in silicon tetrachloride, SiCl₄, are polar, but the molecule is not.

……………………………………………………………………………………………

(Total 2 marks)

44. The diagrams below represent the structures of Iodine, Sodium and Sodium Iodide.

(a) (i) Identify which of the structures (A, B and C) correspond to Iodine, Sodium and Sodium Iodide.

………………………………………………………………………………

(1)

(ii) State the type of bonding in each structure.

………………………………………………………………………………

………………………………………………………………………… (3)

(b) (i) Sodium and sodium iodide can both conduct electricity when molten, but only Sodium can conduct electricity when solid. Explain this difference in conductivity in terms of the structures of sodium and Sodium Iodide.

………………………………………………………………………………

…………………………………………………………………………(4)

(ii) Explain the high volatility of Iodine compared to Sodium and Sodium Iodide.

………………………………………………………………………………

…………………………………………………………………………(2)

(Total 10 marks)

45. (i) Draw Lewis (electron dot) structures for CO₂ and H₂S showing all valence electrons.

(2)

(ii) State the shape of each molecule and explain your answer in terms of VSEPR theory.

CO₂ .............................................................................................................................

.....................................................................................................................................

H₂S .............................................................................................................................

.....................................................................................................................................

(4)

(iii) State and explain whether each molecule is polar or non-polar.

.....................................................................................................................................

(2)

(Total 8 marks)

46. Identify the strongest type of intermolecular force in each of the following compounds.

CH₃Cl ...................................................................................................................................

CH₄ .......................................................................................................................................

CH₃OH .................................................................................................................................

(Total 3 marks)

47. (a) An important compound of nitrogen is ammonia, NH₃. The chemistry of ammonia is influenced by its polarity and its ability to form hydrogen bonds. Polarity can be explained in terms of electronegativity.

(i) Explain the term electronegativity.

………………………………………………………………………………

(2)

(ii) Draw a diagram to show hydrogen bonding between two molecules of NH₃.

The diagram should include any dipoles and/or lone pairs of electrons

………………………………………………………………………………

……………………………………………………………………………(3)

(iii) State the H–N–H bond angle in an Ammonia molecule.

……………………………………………………………………………(1)

(iv) Explain why the Ammonia molecule is polar.

………………………………………………………………………………

……………………………………………………………………………(1)

(b) Ammonia reacts with hydrogen ions forming Ammonium ions, NH₄⁺.

(i) State the H–N–H bond angle in an ammonium ion.

……………………………………………………………………………(1)

(ii) Explain why the H–N–H bond angle of NH3 is different from the H–N–H bond angle of NH₄⁺; referring to both species in your answer.

………………………………………………………………………………

……………………………………………………………………………(3)

(Total 11 marks)

48. State the type of bonding in the compound SiCl₄. Draw the Lewis structure for this compound.

…………………………………………………………………………………....................................…………

……………………………………………………………………………………………..........................…………

(Total 3 marks)

49. Outline the principles of the valence shell electron pair repulsion (VSEPR) theory.

……………………………………………………………………………………………..........................…………

……………………………………………………………………………………………..........................…(3)

50. (i) Use the VSEPR theory to predict and explain the shape and the bond angle of each of the molecules SCl₂ and C₂Cl₂

………………………………………………………………………………………

(6)

(ii) Deduce whether or not each molecule is polar, giving a reason for your answer.

………………………………………………………………………………………

(3)

(Total 9 marks)

51. Draw a Lewis structure of a water molecule, name the shape of the molecule and state and explain why the bond angle is less than the bond angle in a tetrahedral molecule such as methane.

(Total 4 marks)

52. Predict and explain the order of the melting point for propanol, butane and propanone with reference to their intermolecular forces.

(Total 4 marks)

53. The elements Sodium, Aluminium, Silicon, Phosphorus and Sulphur are in Period 3 of the periodic table.

Describe the metallic bonding present in aluminium and explain why Aluminium has a higher melting point than sodium.

..............................................................................................................................................

(Total 3 marks)

54. Draw the Lewis structure of NCl₃. Predict, giving a reason, the Cl – N – Cl bond angle in NCl₃.

(Total 3 marks)

55. Arrange the following in decreasing order of bond angle (largest one first), and explain your reasoning.

NH₂^–, NH₃, NH₄⁺

(Total 5 marks)

56. (i) Outline the principles of the valence shell electron pair repulsion (VSEPR) theory.

(3)

(ii) Use the VSEPR theory to deduce the shape of H₃O⁺ and C₂H₄. For each species, draw the Lewis structure, name the shape, and state the value of the bond angle(s).

(6)

(iii) Predict and explain whether each species is polar.

(2)

(iv) Using the Data Booklet, predict and explain which of the bonds O-H, O-N or N-H would be most polar.

(2)

(Total 13 marks)

57. Predict and explain which of the following compounds consist of molecules:

NaCl, BF₃, CaCl₂, N₂O, P₄O₆, FeS and CBr₄.

(Total 2 marks)

58. Diamond, graphite and C₆₀ fullerene are three allotropes of carbon.

(i) Describe the structure of each allotrope.

(3)

(ii) Compare the bonding in diamond and graphite.

(2)

(Total 5 marks)

59. State two physical properties associated with metals and explain them at the atomic level.

(Total 4 marks)

60. (a) Draw the Lewis structure of Methanoic acid, HCOOH.

(1)

(b) In Methanoic acid, predict the bond angle around the

(2)

(i) Carbon atom. ....................................................................................................

(ii) Oxygen atom bonded to the Hydrogen atom. ...................................................

(c) State and explain the relationship between the length and strength of the bonds between the carbon atom and the two Oxygen atoms in Methanoic Acid.

......................................................................................................................................

(3)

(Total 6 marks)