3.1.3.3 Metallic bonding Quiz: AQA Chemistry, Unit 1

The 20 questions

1. What is metallic bonding?

   • Sharing of electron pairs between two atoms, which are held together by a covalent bond
   • Electrostatic attraction between positive and negative ions that are held in a fixed lattice
   • Attraction between delocalised electrons and positive ions arranged in a lattice
   • Attraction between molecules through hydrogen atoms bonded to nitrogen, oxygen or fluorine

2. Why are metals good conductors of electricity?

   • Delocalised electrons can move through the lattice
   • Metal lattices contain molecules with dipoles
   • Metal atoms share electrons in covalent bonds
   • Positive ions can move freely through the lattice

3. What does the term 'sea of delocalised electrons' describe?

   • Electrons localised in covalent molecules
   • Lone pairs on oxygen in water
   • Delocalised electrons in a metallic lattice
   • Electrons in an ionic compound

4. Why are metals malleable?

   • Covalent bonds break and reform easily between layers of atoms, so the structure bends without shattering or cracking
   • Ions are arranged in rigid molecules that bend under stress, so the whole structure can deform easily without breaking
   • Layers of positive ions can slide over each other while the delocalised electrons still hold the structure together
   • Metals contain no bonds at all, so the atoms are held only by weak forces that let them move freely past each other

5. Which metal in Period 3 has the most delocalised electrons per atom?

   • Magnesium
   • Aluminium
   • Potassium
   • Sodium

6. Metals have high melting points. Which best explains the strength of metallic bonding?

   • Strong attraction between delocalised electrons and the positive ions
   • Dative covalent bonds between metal atoms, which share electron pairs from one atom
   • Weak van der Waals forces between the atoms, which hold them only loosely together
   • Hydrogen bonds between layers of metal atoms, which hold the layers together firmly

7. Which statement about a metallic lattice is true?

   • The lattice contains negative ions that are strongly attracted to the positive ions
   • Atoms form discrete molecules that are held together by intermolecular forces between them
   • Positive ions are arranged in a regular lattice surrounded by delocalised electrons
   • Electrons are localised between pairs of atoms, forming directional covalent bonds

8. Compare sodium and magnesium. Which has the higher melting point, and why?

   • Sodium, because its ions are larger and attract electrons more strongly
   • Magnesium, because magnesium has covalent bonds
   • Magnesium, because it has more delocalised electrons per atom and stronger attraction
   • Sodium, because it has fewer delocalised electrons

9. Which property of metals is best explained by the presence of delocalised electrons?

   • Fixed crystal shape in molten form
   • Solubility in water at room temperature
   • Brittleness when a force is applied
   • Electrical conductivity in the solid state

10. Which ions and electrons are present in the metallic lattice of calcium?

    • Ca2- ions and bonding pairs of electrons
    • Ca2+ and Cl- ions
    • Ca+ ions and localised electrons
    • Ca2+ ions and delocalised electrons

11. How many delocalised electrons does one atom of magnesium contribute to the metallic lattice?

    • 1
    • 0
    • 2
    • 3

12. Which statement correctly compares metallic bonding with ionic bonding in sodium chloride?

    • Metallic bonding is non-directional, whereas ionic bonding is between specific oppositely charged ions in a fixed arrangement
    • Metallic bonding is a sharing of electron pairs, while ionic bonding has no electrons involved at all
    • Both involve discrete molecules that are held together by weak intermolecular forces in the lattice
    • Metallic bonds are always weaker than hydrogen bonds, so metals melt more easily than ionic solids

13. Why do metals usually conduct heat well?

    • Positive ions have no charge, so they cannot carry energy from one part of the metal
    • Delocalised electrons carry kinetic energy through the lattice
    • Metals contain permanent dipoles that absorb heat and release it only at the surface
    • Metallic bonds are weak, so energy cannot pass between the atoms of the metal easily

14. How many delocalised electrons does each atom of a Group 1 metal contribute?

    • Two
    • Three
    • None
    • One

15. Why are alloys usually harder than pure metals?

    • Alloys contain no delocalised electrons, so the lattice is held together by fixed bonds
    • Atoms of different sizes disrupt the regular layers, so the layers slide less easily
    • Alloys contain a covalent network throughout, which locks every layer firmly in place
    • Alloys contain ionic bonds that are stronger than the metallic bonds in pure metals

16. Why do Group 1 metals have lower melting points than Group 2 metals in the same period?

    • Group 1 atoms have more protons than Group 2 atoms, so the attraction on the delocalised electrons is weaker
    • Group 1 metals contain hydrogen bonds between layers, which are weaker than the metallic bonds of Group 2
    • Group 1 atoms contribute one delocalised electron each and form larger ions, so the metallic bonding is weaker
    • Group 1 metals contain covalent bonds that are much weaker than the metallic bonds of Group 2 metals

17. Two metals have the same number of delocalised electrons per atom, but one has smaller positive ions. Which has stronger metallic bonding?

    • Neither, because metallic bonding is not electrostatic and so the ion size has no effect
    • The metal with smaller positive ions, because its ions are closer to the delocalised electrons
    • They are equal, because the number of delocalised electrons per atom is the same in both
    • The metal with larger positive ions, because the delocalised electrons are further away from them

18. Why does the electrical conductivity of a metal decrease as its temperature increases?

    • Electrons leave the lattice at high temperature, which removes the carriers from the metal
    • The ions vibrate more, increasing collisions with the moving delocalised electrons
    • Delocalised electrons are used up as the temperature rises, so fewer carriers remain available
    • The ions become charged as the temperature rises, which reduces the number of free carriers

19. How many moles of delocalised electrons are present in 1 mol of aluminium?

    • 27 mol
    • 1 mol
    • 3 mol
    • 2 mol

20. Why do metals usually have high densities?

    • Metals contain hydrogen bonds between layers that pull the atoms closer together
    • Metals have many lone pairs of electrons that fill the spaces between atoms
    • Atoms are closely packed in a lattice, giving a large mass per unit volume
    • Metal atoms have covalent bonds that hold them tightly in place

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