Lesson 2A.1

2A.1 Ionic bonding and ionic radii Quiz: Pearson Edexcel Chemistry, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 2A.1, Ionic bonding and ionic radii: 20 multiple choice questions for the Pearson Edexcel Chemistry (9CH0), Unit 2: Bonding and Structure, written with Revision Ninja.

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The 20 questions

  1. What is ionic bonding?

    • The sharing of a pair of electrons between two nuclei
    • The strong electrostatic attraction between oppositely charged ions
    • The attraction between metal ions and delocalised electrons
    • The weak attraction between temporary dipoles in neighbouring molecules

  2. Which ion of magnesium is formed when a Mg atom loses two electrons?

    • Mg2-
    • Mg2+
    • Mg-
    • Mg+

  3. Which change makes ionic bonding stronger?

    • Larger ions with higher charges, which increase the attraction but spread it over a wider space
    • Smaller ions with higher charges
    • Smaller ions with lower charges, which reduce the attraction between the oppositely charged ions
    • Larger ions with lower charges, which spread the electrostatic attraction over a wider space

  4. Which species is isoelectronic with Na+?

    • Ne
    • Cl
    • Ar
    • Mg

  5. What is the electron configuration of the O2- ion?

    • 1s2 2s2 2p4
    • 1s2 2s2 2p6 3s2
    • 1s2 2s2 2p2
    • 1s2 2s2 2p6

  6. Which observation provides evidence for the existence of ions in an ionic compound?

    • Sodium chloride is a gas at room temperature, showing that its particles are small and not held in a lattice
    • Solid sodium chloride conducts electricity well, showing that its ions are free to move through the solid
    • Molten sodium chloride conducts electricity and its ions migrate to the electrodes
    • Sodium chloride dissolves readily in hexane, showing that the ions are strongly attracted to the non-polar solvent

  7. Which of N3-, O2-, F- and Na+ has the largest ionic radius?

    • F-
    • Na+
    • N3-
    • O2-

  8. Which ion has the smallest radius among Al3+, Mg2+, Na+ and F-?

    • Na+
    • Mg2+
    • Al3+
    • F-

  9. Which compound has the strongest ionic bonding?

    • MgO
    • NaF
    • NaCl
    • KCl

  10. Which electron configuration is correct for the Al3+ ion?

    • 1s2 2s2 2p4
    • 1s2 2s2 2p6
    • 1s2 2s2 2p6 3s2
    • 1s2 2s2 2p6 3s2 3p1

  11. Why do ionic radii increase down Group 1?

    • Electrons are removed from the inner shell as the group is descended, which shrinks the ion in size
    • Each ion has an extra electron shell, so the ion is larger
    • Nuclear charge decreases down the group, so the nucleus holds the outer electrons less tightly than before
    • Ions gain more neutrons down the group, which makes each ion larger in overall size and in mass

  12. N3- and Al3+ are isoelectronic. Which has the larger ionic radius and why?

    • Al3+, because it has more protons attracting its electrons, which pulls the same ten electrons more tightly
    • N3-, because it contains more neutrons in its nucleus, which increases the overall size of the whole ion
    • Al3+, because it has a higher charge, so its electron cloud is larger and more spread out in space
    • N3-, because its lower nuclear charge (7 against 13) pulls the same 10 electrons less strongly

  13. Sulfur atoms form ions with what charge in forming sulfide?

    • 2-
    • 2+
    • 4+
    • 6-

  14. What is the formula of the ionic compound formed from aluminium and oxygen?

    • Al2O
    • Al3O2
    • Al2O3
    • AlO

  15. What is the formula of magnesium nitride?

    • Mg3N2
    • Mg2N3
    • Mg3N
    • MgN

  16. Explain why ionic bonding in MgO is stronger than in NaCl.

    • Mg2+ and O2- have lower charges than Na+ and Cl-, so they attract each other more strongly overall in the lattice
    • MgO has more neutrons than NaCl, which hold the ions more tightly together in the crystal lattice of the solid
    • Mg2+ and O2- have higher charges and smaller ions than Na+ and Cl-, so the electrostatic attraction is stronger
    • NaCl has smaller ions than MgO, which means its ions sit closer together and bond more strongly in the solid

  17. An ion X2+ has 10 electrons. What is the formula of its fluoride?

    • MgF
    • MgF3
    • Mg2F
    • MgF2

  18. Which of O2-, F-, Na+ and Mg2+ has the largest ionic radius?

    • F-, because it has the highest electronegativity of the four ions, which gives it the largest radius
    • Na+, because it has the largest number of neutrons, which increases the overall size of its ion
    • Mg2+, because it has the most protons in its nucleus, which spreads its electron cloud the furthest out in space
    • O2-, because it has the fewest protons per electron, so the same 10 electrons are least strongly pulled in

  19. Put these ionic radii in order of decreasing size: Na+, Mg2+, Al3+.

    • Al3+ > Mg2+ > Na+
    • Na+ > Mg2+ > Al3+
    • Mg2+ > Na+ > Al3+
    • Na+ = Mg2+ = Al3+

  20. Explain why Group 2 oxides have higher melting temperatures than Group 1 oxides.

    • Group 2 oxides are small molecules with many London forces that hold them together very strongly indeed
    • Group 2 oxides contain covalent bonds that are much stronger than the ionic bonds found in Group 1 oxides
    • Group 1 oxides have more ions per formula unit, which makes their lattices weaker and easier to melt apart
    • Group 2 ions carry 2+ and 2- charges, giving stronger electrostatic attraction than 1+ and 2- combinations

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