Questions on Chemical Bonding

1. Explain briefly why NaCl is more ionic than MgCl2?

2. Explain briefly why NaCl is more ionic than NaI?

3. Which of the following compounds is more ionic, NaCl and AlCl3?

4. Which of the following compounds is more ionic, NaCl and LiCl?

5. Which of the following compounds is more ionic, NaF and NaCl?

6. Which of the following pair is more ionic;

(i) NaCl and CaCl2;
(ii) K2O and Na2O;
(iii) KF and KCl.

7. Arrange the following in order of increasing ionic character; LiCl, NaCl and RbCl?

8. Arrange the following in order of increasing ionic character; LiCl and Li2S?

9. Arrange the following in order of increasing ionic character; LiCl, LiBr, LiI and LiF?

10. Deduce which of the following compounds is more ionic;

(i) LiBr and KBr;
(ii) MgF2 and MgI2

11. State, giving reasons the species which has greater lattice energy;
(i) MgCl2 and LiCl;
(ii) MgO and MgS;
(iii) MgO and NaF

12. The lattice energies of three sodium halides are as follows;

Compound NaF NaBr NaI
Lattice energy 899KJ/mol 719KJ/mol 670KJ/mol

Suggest reasons for this trend?

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13. Under the table of electronegativities given below, arrange the following compounds
in decreasing order of ionic character and give reasons for the order; PH3, GeCl4, CsF.

Atom Electronegativity
Cl 3.0
P 2.1
H 2.1
Ge 1.8
F 4.0
Cs 0.7
14. Consider the following pairs of bonds
C-N and C-H
C-O and C-N
C-F and C-O
(i) Which bond in each pair is more polar? Explain
(ii) Arrange the bonds in increasing order of polarity.

15. Explain what happens when wax is dissolved in benzene?

16. Arrange the following in increasing order of metallic bond strength; Al, Na and Mg?

17. Suggest reasons to explain why magnesium has a higher melting point than sodium?

18. Suggest reasons to explain why alkali metals are soft?

19. Consider the following pairs of elements;

(Na, O), (Al, Cl), (Al, F), (O, F), and (P, H)
(i) Which of the above pairs of elements form ionic bonds;
(ii) Which of the remaining pairs form the least polar bonds?

20. Describe the nature and formation of bonding in NaCl?

21. Explain briefly how the bonds in HCl and Cl2 are formed?

22. Give two differences in the properties of NaCl(s) and Cl2(g)?

23. Explain what happens when crystal of NaCl is dissolved in water?

24. Assign reasons to the following statements; NaCl solution conducts electricity
whereas glucose solution does not.

25. Explain what happens when grease-stained material is washed with kerosene to
remove the grease.

26. Consider each of the following substances in their solid states; Zinc, Neon, Water,
Diamond, Sodium Chloride; select from the list above;

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 (i) A solid in which the atoms are covalently bonded in the network;
(ii) A solid which is a good conductor of electricity;
(iii) A solid which is a poor electrical conductor but conducts on melting.

27. For each of the substances; Na(s), H2(g), NaH(s), and NH4Cl(s) state;
(i) The type of solid it is (molecular, ionic, metallic);
(ii) The species which occupy the lattice points;
(iii) The name of the intermolecular forces holding the units together.

28. Identify the types of chemical bonding that exist in CuSO4.5H2O?

29. Use the information provided in the table below to answer the questions that follow;
Elements W X Y Z
Atomic 8 17 18 19
number

(i) What type of bond exist between Z and X in the compound ZX;
(ii) Write the formular of the compound formed when Z combines with W;
(iii) What type of bond exist between W in its diatomic molecule;
(iv) State with reasons whether or not a bond would be formed between two atoms
of Y;
(v) Which of the elements is a halogen;
(vi) Which of the elements is a metal?

30. Use the information provided in the table below to answer the following questions.
Elements Mass number Atomic number
A 16 8
X 37 17
R 31 15
Y 18 8
Q 23 11

(i) Which of the elements is an alkali metal;

(ii) Which atom will readily form an ion with a single negative charge;
(iii) How many electrons are there in R;
(iv) Which of the atoms are isotopes of the same element;
(v) What type of bond exist between Q and X in the compound QX;
(vi) Write the formular of the compound formed when Q combines with Y;
(vii) What type of bond exist between atoms of A in its diatomic molecules;
(viii) Which of the elements is a halogen?

31. What is meant by the term polarizing power of a cation?

32. State the factors that enhance greater polarizing power?

33. State the factors that determine the covalent character in a compound?

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34. Deduce which of the following compounds is more covalent;

(i) NaCl and NaI;

(ii) MgBr2 and CaBr2

35. Explain what factors would determine whether the bond in compound C-X is
covalent or ionic?

36. Distinguish between an electrovalent bond and a covalent bond?

37. The periodic properties of some elements are shown in the following table. Study the
table and use it to answer the questions that follow;

Element 1st I.E/KJmol-1 2nd I.E/KJmol-1 E.A KJmol-1 Electronegativity

M 740.46 1455.72 -12.2 1.2
Q 1318.80 3404.52 34.0 3.2
R 1687.56 3388.14 -79.5 4.0
Z 1316.70 ---------- -17.4 2.1
X 420.42 3081.12 -11.5 0.8

(a) Select two elements which can form;

(i) Ionic bond;
(ii) Covalent bond
(b) Give reasons for your answers in each case.

38. Define the following terms;

(i) Ionic bond;
(ii) Covalent bond;
(iii) Co-ordinate covalent bond;
(iv) Polar covalent;
(v) Metallic bond.

39. State the conditions or factors which favour the formation of all the bonds listed
below;
(i) Ionic bond;
(ii) Covalent bond;
(iii) Co-ordinate covalent bond;
(iv) Polar covalent;
(v) Metallic bond.

40. State the difference between a pure covalent bond and a co-ordinate bond?
Wassce 2023

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41. CO2 and SiO2 are both covalent compounds. Explain briefly why CO2 is a gas
whereas SiO2 is a solid under ordinary conditions?
Wassce 2023
42. An element X reacts with bromine to form an ionic compound XBr2.
(i) State with reasons the physical state of XBr2 at room temperature;
(ii) State with reasons whether X is a metal or a non-metal;
(iii) Predict two properties of XBr2 other than its physical state;
(iv) State the charge of an ion of X?
Wassce 2023

43. Explain briefly why benzene is soluble in ethanol but insoluble in water?
Novdec 2016

44. Draw the structure of ammonium ion showing the type of bonds present?

45. State the type of chemical bond in the compounds formed between each of the
following pairs of elements;

(i) 20Ca and 8O;

(ii) 6C and 17Cl.

State one property of the compound formed in each case?

Wassce 2019
46. (a) Explain what is meant by the term electronegativity. How is electronegativity
related to the type of bond formed between two atoms?

(b)You are given the following electronegativity values;

Elements H C F Cl Br Ba Rb
electronegativity 2.1 2.5 4.0 3.0 2.8 0.9 0.8

Predict on the basis of these values the types of bond present in;
(i) RbCl;
(ii) HF;
(iii) BaH2;
(iv) ClBr.

47. Arrange the following in increasing order of covalency. Give reasons for the order
BCl3, NCl3, BeCl2.

48. Suggest reasons to explain why lithium salts are commonly hydrated whilst the
corresponding salts of sodium are usually anhydrous?

49. Explain why group II elements frequently form hydrated salts while corresponding
salts of group 1 are anhydrous?

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50. State, giving reasons, whether the statement below is true or false; of the alkali metal
ions, Li+ has the highest mobility in aqueous solution and therefore conducts
electricity best?

51. Explain why conducting measurements of M+ in aqueous solution give the order;

Cs+ > Rb+ > K+ > Na+ > Li+

52. Explain why LiCl dissolves in water whilst LiI dissolves in most organic solvents?

53. Explain which of the potassium compounds of three elements F, Cl and Br, you would
expect to have;

(i) The greatest covalent character;

(ii) The greatest ionic character.

54. Give two physical properties of metals and indicate how each of these properties
contribute to the use of the metal?

55. What are van der waals forces?

56. State two physical properties of liquids that could be increased as a result of hydrogen
bonding?

57. Arrange the halogens Cl2, Br2, and I2 in order of increasing strength of van der waals
forces. Explain your order?

58. Arrange the following in order of increasing enthalpy change of vapourisation; H2O,
CH4 and H2S.

59. Explain why iodine (I2) is solid but chlorine (Cl2) is a gas?

60. Explain why the boiling point of H2O is greater than that of H2S?

61. Explain why glucose dissolves in water?

62. State giving reasons whether the following statement is true or false. Of the two
hydrogen bonds represented by the broken lines, the former is stronger than the latter.

N-H------F
O-H------F

63. Arrange the following hydrogen halides in order of increasing boiling points. Explain
your order; HCl. HBr, HF

64. Explain why H2O boils at 100oC why H2S boils at -58oC?

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65. Arrange each of the following sets of compounds in order of increasing boiling points
and account for the order;

(i) CH4, H2O and H2S;

(ii) NaH, CS2 and CO2

66. Name the kind of bond or attractive force which has to be overcome in order to melt
the solid forms of each of the compounds.
(i) CO2;
(ii) SiO2;
(iii) KCl.
Indicate in each how the forces arise or how they are formed?
67. What are the forces operating between the molecules or units in the condensed states
of each of the following substances;
LiCl
HF
Cu
CCl4
Diamond (C)
Glucose
H2
Pentane

68. State whether each of the following statement is true or false. If it is false, give your
reason and cite an example which does not agree with the statement.
(i) All substances with high melting points are ionic;
(ii) Boiling points always increase with increasing molecular mass;
(iii) Van der waals forces exist between all molecules;
(iv) Hydrogen bonding exists in all compounds containing hydrogen.

69. Explain what do you understand by the term entropy?

70. For each of the following chemical or physical processes indicate whether the entropy
is likely to increase, decrease or remain the same, explaining your reasoning;

(i) H2(g) + C2H4(g) → C2H6(g);

(ii) 2NaNO3(s) → 2NaNO2(s) + O2(g);
(iii) N2(g) + O2(g) → 2NO(g)
(iv) The adsorption of hydrogen gas onto the surface of carbon particles.

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 71. For the following reactions or processes state, with reasons, whether entropy increases
or decreases or stays approximately the same.
(i) 2CO(g) + O2(g) → 2CO2(g);
(ii) NaCl(s) → Na+(aq) + Cl-(aq);
(iii) C(s) + CO2(g) → 2CO(g);
(iv) nC(s) + nH2(g) → n⌠C(s) ---H2⌡;
(v) Fe3O4(s) + 4H2(g) → 3Fe(s) + 4H2O(g)

72. For each of the processes given below, state giving reasons, whether there is an
increase or decrease in entropy;
(i) Crystallization of NaCl from sea water;
(ii) Decomposition of Calcium trioxocarbonate (IV);
(iii) Conversion of gaseous sulphur (IV) oxide to gaseous sulphur (VI) oxide;
(iv) Dimerization of nitrogen (IV) oxide to dinitrogen tetraoxide;
(v) Dissolution of ammonium chloride in water;
(vi) Condensation of water vapour;
(vii) Adsorption of carbon dioxide gas by charcoal.

“Sometimes people do not know the strains their actions and inactions put on other people”
ORTEGA