Giant covalent structures

This question is about bonding and structures.

Figure 10 represents two models of sodium chloride.

Give two limitations of model A compared with model B.

Aluminium sulfate consists of the ions:

What is the formula of aluminium sulfate?

Metals have metallic bonding.

Suggest one reason why aluminium metal conducts electricity better than sodium metal.

Silicon dioxide and the polymer poly(ethene) are solid substances.

Compare silicon dioxide with the polymer, poly(ethene).

Answer in terms of structure and bonding.

Structure and bonding is used to explain properties of compounds.

Metal atoms react with non-metal atoms to form ions.

Which group of elements does not form ions? Tick (✓) one box.

Potassium reacts with chlorine to produce potassium chloride (KC l). Figure 6 shows what happens to the electrons in the outer shells when a potassium atom reacts with a chlorine atom.

Describe what happens when a potassium atom reacts with a chlorine atom to produce potassium chloride. Answer in terms of electrons.

In solid ionic compounds, oppositely charged ions attract to form a giant structure. Which structure represents the arrangement of ions in solid potassium chloride? Tick (✓) one box.

Non-metal atoms share electrons to form covalent bonds.

Water (H₂O) is a covalent molecule. Table 2 shows the number of electrons in the outer shells of hydrogen atoms and

Figure 7 shows part of a dot and cross diagram for a molecule of water. Complete the dot and cross diagram. You should only show electrons in the outer shells.

Figure 7

Silica has a giant covalent structure. Figure 8 represents the structure of silica.

Determine the ratio of silicon (Si) atoms to oxygen (O) atoms in silica. Use Figure 8.

Polymers have very large molecules. Figure 9 represents part of the structure of a polymer.

What holds polymer molecule 1 and polymer molecule 2 together in a polymer? Tick (✓) one box.

Describe the trend shown in Figure 10.

This question is about structure and bonding. Figure 6 represents part of the structure of silicon dioxide.

What type of structure is silicon dioxide? Tick (✓) one box.

Each oxygen atom forms two bonds. What is the number of bonds formed by each silicon atom? Use Figure 6.

Figure 7 represents part of a fullerene.

Complete the sentence. Choose the answer from the box.

Complete the sentence. Choose the answer from the box.

The fullerene molecule shown in Figure 7 is made from

What is the fullerene molecule shown in Figure 7 used for? Tick (✓) one box.

Figure 8 represents part of the structure of a polymer.

What holds the atoms together in a polymer chain? Tick (✓) one box.

Complete the sentence. Choose the answer from the box.

In Figure 8 the polymer chains are held together by

Figure 9 represents part of the structures of:

• magnesium metal

• a magnesium alloy.

Calculate the percentage of copper atoms in the alloy. Number of magnesium atoms in the alloy = Number of copper atoms in the alloy = Total number of atoms in the alloy =

Explain why the magnesium alloy is harder than magnesium metal. Use Figure 9.

This question is about substances with covalent bonding.

Figure 12 shows a ball and stick model of a water molecule (H₂O).

Suggest one limitation of using a ball and stick model for a water molecule.

Ice has a low melting point. Water molecules in ice are held together by intermolecular forces. Complete the sentence. Ice has a low melting point because the intermolecular forces are.

Figure 13 shows the structure of a molecule.

What is the molecular formula of the molecule in Figure 13 ?

Diamond has a giant covalent structure.

What is the number of bonds formed by each carbon atom in diamond? Tick (✓) one box.

Give two physical properties of diamond.

Name two other substances with giant covalent structures.

This question is about substances with covalent bonding.

Figure 2 shows a ball and stick model of a water molecule (H₂O).

Suggest one limitation of using a ball and stick model for a water molecule.

Ice has a low melting point. Water molecules in ice are held together by intermolecular forces. Complete the sentence. Ice has a low melting point because the intermolecular forces are.

Figure 3 shows the structure of a molecule.

What is the molecular formula of the molecule in Figure 3 ?

Diamond has a giant covalent structure.

What is the number of bonds formed by each carbon atom in diamond? Tick (✓) one box.

Give two physical properties of diamond.

Name two other substances with giant covalent structures.