IGCSEChemistryCambridge (CIE)Exam Questions2. Atoms, Elements & CompoundsSimple Molecules & Covalent Bonds

Simple Molecules & Covalent Bonds (Cambridge (CIE) IGCSE Chemistry): Exam Questions

Exam code: 0620 & 0971

2 hours33 questions

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Simple Molecules & Covalent Bonds

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1
1 mark

Which of the following compounds are formed by covalent bonding?

1

Potassium fluoride

2

Propane

3

Carbon dioxide

4

Lithium bromide

  • 2 and 3

  • 2 and 4

  • 1, 2 and 3

  • 1 and 4

Choose your answer

2
1 mark

Which row correctly describes a simple covalent compound?

 

low melting point

high boiling point

A

✓

✓

B

cross times

✓

C

cross times

cross times

D

✓

cross times

    Choose your answer

    3
    1 mark

    Which statement about bonding is not correct?

    • Covalent bonding involves non metal elements.

    • Covalent bonding involves electron sharing.

    • Covalent bonding involves electron transfer.

    • Covalent bonding does not involve metal elements.

    Choose your answer

    4
    1 mark

    Ammonia is a covalent compound consisting of one nitrogen atom bonded to three hydrogen atoms.

    Which statement is correct for a molecule of ammonia?

    • The number of shared pairs of electrons is five

    • The number of shared pairs of electrons is three

    • There are single covalent bonds between the hydrogen atoms.

    • Each hydrogen atom donates one pair of electrons to the central nitrogen atom.

    Choose your answer

    5
    1 mark

    Extended Only 

    The structure of propane is shown below

    Which correctly explains why propane can not conduct electricity?

    • There are weak intermolecular forces between molecules of propane

    • The covalent bonds in propane are strong

    • There are no free electrons able to move and carry a charge

    • Propane has a low boiling point

    Choose your answer

    6
    1 mark

    Lithium hydroxide reacts with hydrochloric acid to form lithium chloride and water.

    Which row describes correctly the properties of the products and the final reaction mixture?

    melting point of lithium chloride

    melting point of water

    electricity conduction of the reaction mixture

    A

    high

    high

    good

    B

    high

    low

    good

    C

    low

    high

    poor

    D

    low

    low

    poor

      Choose your answer

      1
      1 mark

      Atoms P and Q have electronic structures as shown in the diagram. They react together to form a covalent compound.

      q1-2-3-mcq-medium-cie-igcse-chemistry

      What is the formula of the compound?

      • P2Q3

      • P3Q

      • P3Q2

      • PQ4

      Choose your answer

      2
      1 mark

      The atom of element Z has 6 electrons in its outer shell. How would this element react?

      • It shares two electrons with four from another atom to form two covalent bonds

      • It shares four electrons with four from another atom to form four covalent bonds

      • It shares four electrons with two from another atom to form two covalent bonds

      • It shares two electrons with two from another atom to form two covalent bonds

      Choose your answer

      3
      1 mark

      CH4, H2O and HCl are covalent compounds.

      Which atoms in these compounds do not use all of their outer shell electrons in bonding?

      • C and O

      • C and H

      • Cl and O

      • Cl and C

      Choose your answer

      4
      1 mark

      The electronic configurations of four different atoms are shown below.

      q4-2-3-mcq-medium-cie-igcse-che

      Which atoms form covalent compounds?

      • W and X

      • W, X and Y

      • W and Z

      • X, Y and Z

      Choose your answer

      5
      1 mark

      Extended Only

      Which of the following molecules contains only single covalent bonds?

      • N2

      • F2

      • O2

      • CO2

      Choose your answer

      6
      1 mark

      Diagrams 1 and 2 show the electron arrangements in molecules of water and methane.

      Left: water. Central O bonded to two H, one shared pair in each O–H bond, two lone pairs on O. Right: methane. Central C bonded to four H with one shared pair each, and non bonding pair of electrons in the outer shell of each hydrogen

      Which row describes the diagrams?

      water diagram

      methane diagram

      A

      correct

      incorrect

      B

      correct

      correct

      C

      incorrect

      incorrect

      D

      incorrect

      correct

        Choose your answer

        1
        1 mark

        Extended Only

        Carbon dioxide is a simple molecular substance in which the molecules are formed by covalent bonding between one carbon atom and two oxygen atoms.

        Which dot and cross diagram below shows the correct outer shell arrangement of electrons in a molecule of CO2?

        q1-2-3-mcq-hard-cie-igcse-che

          Choose your answer

          2
          1 mark

          Extended Only

          A student has drawn a dot and cross diagram to represent a molecule of ethene, C2H4, as shown below.

          q2-2-3-mcq-hard-cie-igcse-che

          What is wrong with the students drawing?

          • The number of electrons shared between the carbon atoms is incorrect.

          • The number of electrons shared between each carbon and hydrogen is incorrect.

          • There is nothing wrong with the drawing.

          • The total number of electrons shared is incorrect.

          Choose your answer

          3
          1 mark

          Extended Only

          Dot and cross diagrams for four covalent molecules are shown below.

          Which diagram is incorrect?

          Diagram showing four molecular structures: A is Cl2, B is HCl, C is H2, D is CO2, with labelled overlapping circles indicating covalent bonds.

            Choose your answer

            4
            1 mark

            Extended Only

            Which statement about methane is correct?

            • It has a high melting point due to strong covalent bonds between atoms 

            • It has a low melting point due to weak covalent bonds between the molecules 

            • It has a low boiling point due to weak intermolecular forces between molecules 

            • It has a high boiling point because of strong intermolecular forces between molecules

            Choose your answer

            5
            1 mark

            Extended Only

            A covalent molecule M contains a total of four shared electrons. 

            What is M?

            • Carbon dioxide

            • Oxygen

            • Nitrogen 

            • Methane

            Choose your answer

            6
            1 mark

            The displayed formula of ethanoic acid is shown.

            Displayed structural formula of ethanoic acid: left carbon has three C–H bonds and one C–C bond; right carbon has C–C, C=O double bond, and C–O–H.

            Which row shows the total number of shared electrons and the total number of non-bonding electrons in one molecule of ethanoic acid?

            total number of shared electrons

            total number of non-bonding electrons

            A

            14

            0

            B

            14

            8

            C

            16

            0

            D

            16

            8

              Choose your answer