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DP IB Chemistry: SL

Topic Questions

Home / IB / Chemistry: SL / DP / Topic Questions / 4. Chemical Bonding & Structure / 4.1 Ionic & Covalent Bonding / Structured Questions: Paper 2


4.1 Ionic & Covalent Bonding

Question 1a

Marks: 5
a)

Magnesium fluoride is a white crystalline salt that has a giant ionic lattice structure.

State whether the following substances conduct electricity when solid or molten, and explain your answers in terms of the particles involved:

  • magnesium
  • magnesium fluoride
  • boron tribromide

[5]

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    Question 1b

    Marks: 2
    b)
    Sodium chloride and iodine are both solids. Sodium chloride does not melt until it reaches a temperature of 1074 K yet iodine sublimes when heated gently, giving off purple vapours. Sodium chloride will conduct electricity when molten and iodine is a very poor conductor of electricity.
    State the type of crystal structure for each of iodine and sodium chloride.
    [2]
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      Question 1c

      Marks: 2
      c)

      Explain why iodine vaporises easily.

      [2]

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        Question 1d

        Marks: 3
        d)
        Explain the differences in the electrical conductivity of sodium chloride and iodine.
        [3]
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          Question 2a

          Marks: 2
          a)
          The nitrate (V) ion, NO3-, is a polyatomic ion, bonded by covalent bonds. 

          The three oxygen atoms are bonded by one single covalent bond, one double covalent bond and one dative covalent bond.

          Draw the Lewis structure for NO3-

          [2]

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            Question 2b

            Marks: 2
            b)
            An ionic compound has the empirical formula H4N2O3
            Suggest the formulae of the ions present in this compound.
            [2]
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              Question 2c

              Marks: 4
              c)
              The compounds SO2 and MgO are both oxides but with different melting points as shown below.

              Compound

              Melting point / ℃

              SO2

              -72

              MgO

              2852

              Describe the bonding in, and the structure of, SO2 and MgO and explain the difference in their melting points.

              [4]

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                Question 2d

                Marks: 2
                d)
                Ammonia, NH3, has the same crystalline structure as SO2 and yet its melting point is 2℃. Explain the difference in melting point between SO2 and NH3.
                [2]
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                  Key Concepts
                  Intermolecular forces

                  Question 3a

                  Marks: 3
                  a)
                  Silver chloride, AgCl, is a chloride compound that has uses in photography films as well as having antiseptic properties. 

                  Silver chloride has a high melting point and a structure similar to sodium fluoride.

                  Explain why, with reference to structure and bonding, why silver chloride has such a high melting point.

                  [3]

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                    Question 3b

                    Marks: 1
                    b)
                    Cyanide is a fast-acting chemical, which can be found in various forms and can have toxic effects on the body.

                    Draw the Lewis structure for a CN- ion. 

                    Show the outer electrons only.

                    [1]

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                      Key Concepts
                      Lewis structures

                      Question 3c

                      Marks: 3
                      c)

                      Ammonia, NH3, and boron trifluoride, BF3, react together to form NH3BF3. Each of the molecules NH3 and BF3 have different features of its electronic structure which allows them to bond together. Explain how the two molecules bond together and what type of bond is formed between NH3 and BF3.

                      You may use a labelled diagram to help you.

                      [3]

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                        Question 3d

                        Marks: 4
                        d)

                        Aluminium chloride, Al2Cl6, does not conduct electricity when molten but aluminium oxide, Al2O3, does. Explain this in terms of the structure and bonding of the two compounds.

                        [4]

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                          Question 4a

                          Marks: 1
                          a)
                          State why magnesium and oxygen form an ionic compound while carbon and oxygen form a covalent compound.
                          [1]
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                            Question 4b

                            Marks: 2
                            b)
                            Explain why the melting point of phosphorus(V) oxide is lower than that of sodium oxide in terms of their bonding and structure.
                            [2]
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                              Question 4c

                              Marks: 2
                              c)
                              N, N–dinitronitramide N(NO2)3, also known as trinitramide, has been identified as a potentially more environmentally friendly rocket fuel oxidant.
                              Using section 10 of the data booklet, outline how the length of the bond between nitrogen atoms in trinitramide compares with the bond between nitrogen atoms in nitrogen gas, N2.
                              [2]
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                                Question 4d

                                Marks: 2
                                d)
                                Describe the bonding within the carbon monoxide molecule.
                                [2]
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