Bonding, structure & the properties of matter

The properties of materials depend on their structure and bonding.

The table shows some information about four materials.

Draw four lines to connect each material with its correct structure.

Ethene, C₂H₄, has this structure.

Complete the dot and cross diagram for a molecule of ethene.

Only show the outer shell electrons.

Explain why ethene has a low boiling point.

Use ideas about structure and bonding.

The equation shows how ethene can be produced.

The table shows some bond energies.

Calculate the total energy transferred to break all the bonds in the reactant.

Energy transferred to break all the bonds =........ kJ / mol

Calculate the total energy transferred to make all the bonds in the products.

Energy transferred when all the bonds are made =........ kJ / mol

Use your answers to parts (i) and (ii) to calculate the energy change for the reaction.

Energy change =........ kJ / mol

Describe what happens when solid potassium bromide is heated up until it melts into a liquid.

Use ideas about the particle model.

Explain why potassium bromide must be molten for electrolysis to happen.

State the product made at the cathode and write the half equation for the reaction.

The electrolysis is repeated with a solution of potassium bromide.

A student thinks that the same product will be formed at the cathode.

Explain why the student is incorrect.

Name of the different product formed........

Atoms of the same element can have different structures.

Fig. 15.1 shows the structure of two different atoms, Y and Z, of the same element.

Fig. 15.1

What name is given to different atoms of the same element such as Y and Z ?

Write the number of protons, neutrons and electrons in an atom of Z.

Write the mass number of an atom of Z.

Write the name of the element that contains atoms of Y and Z.

Use the Periodic Table.

Complete Fig. 15.2 to show the arrangement of electrons in the ions.

What is the formula of the ionic compound formed when atoms of sodium react with atoms of Y ?

Tick (✓) one box.

Why does sodium react with Y and Z in a similar way?

Tick (✓) one box.

The ionic compound formed in Fig. 15.2 has a high melting point.

Explain why. Use ideas about structure and bonding.

Atoms of the same element can have different structures.

Fig. 11.1 shows the structure of two different atoms, Y and Z, of the same element.

Fig. 11.1

What name is given to different atoms of the same element such as Y and Z ?

Write the number of protons, neutrons and electrons in an atom of Z.

Write the mass number of an atom of Z.

Write the name of the element that contains atoms of Y and Z.

Use the Periodic Table.

Complete Fig. 11.2 to show the arrangement of electrons in the ions.

What is the formula of the ionic compound formed when atoms of sodium react with atoms of Y ?

Tick (✓) one box.

Why does sodium react with Y and Z in a similar way?

Tick (✓) one box.

The ionic compound formed in Fig. 11.2 has a high melting point.

Explain why. Use ideas about structure and bonding.

Which particles in a metal allow it to conduct electricity ?

A Atoms

B Electrons

C Ions

D Protons

13* Hydrogen can form compounds with the Group 7 elements. These compounds are simple covalent molecules.

For example,

When simple covalent molecules are heated, they thermally decompose back into their elements.

For example,

Tables 13.1 and 13.2 show information about the compounds formed from hydrogen and some Group 7 elements.

Table 13.1

Table 13.2

Describe the trends in the properties of the compounds in Table 13.1.

Explain these trends using information from Table 13.2 and ideas about the structure and bonding of simple covalent molecules.

Calcium is a metal found in Group 2 of the Periodic Table.

Draw the arrangement of electrons in an atom of calcium.

Calcium is a metal which can conduct electricity.

Describe the structure and bonding in a metal and explain why metals can conduct electricity.

You can include a diagram in your answer.

Calcium reacts with water to form a solution of calcium hydroxide, Ca(OH)₂, and hydrogen.

Write the balanced symbol equation for the reaction of calcium with water.

Include state symbols in your equation.

A solution of calcium hydroxide is also called limewater.

Name the gas limewater is used as a test for.

Calculate the number of moles in 1.88 g of calcium hydroxide.

Give your answer to 2 significant figures.

Relative atomic mass (A_r): H = 1.0 O = 16.0 Ca = 40.1

Use your answer to part (d)(i) to calculate the concentration of calcium hydroxide in the solution formed.

Give your answer in mol / dm³.

Concentration of solution =........ mol / dm³

A student adds an excess of dilute hydrochloric acid, HC l, to a solution of calcium hydroxide, Ca(OH)₂.

Write the balanced ionic equation for the reaction of dilute hydrochloric acid and a solution of calcium hydroxide.

Describe and explain how the pH of the solution of calcium hydroxide changes as the dilute hydrochloric acid is added until it is in excess.

For many years it was thought that the Group 0 elements were completely unreactive.

However, more recently, scientists have been able to react some of the Group 0 elements with fluorine.

The table shows information about some of the compounds Group 0 elements make with fluorine.

Give a reason why the Group 0 elements are usually described as unreactive.

Give a reason why scientists have used fluorine to make compounds of the Group 0 elements.

Xenon difluoride, XeF₂, is a solid at room temperature. It melts at 129 °C and boils at 155 °C. It does not conduct electricity in any state.

Suggest the structure of xenon difluoride, XeF₂.

Give two reasons for your answer in (c)(i).

Describe how the trend in reactivity of the Group 0 elements is linked to the size of the atoms.

Complete the balanced symbol equation for the reaction of sodium and chlorine to make sodium chloride.

Sodium chloride has a high melting point.

Explain why.

Use ideas about the structure and bonding in sodium chloride in your answer.

Write in the table the state symbol for the solution of sodium chloride.

Tick (✓) one box in each column of the table to show if solid sodium chloride and a

solution of sodium chloride conduct electricity.

Complete the table by writing in the explanation for the student’s results.

Use ideas about the structure and bonding in sodium chloride in your answer.

Solder is a mixture of lead and tin. Solder can be used to join two electrical wires together as shown in Fig. 13.1.

Electrical wire

The table shows how the melting point of solder changes with the percentage of tin it contains.

Plot the data on the grid shown in Fig. 13.2.

On Fig. 13.2 draw a line of best fit through the first three points and a second line of best

fit through the last two points.

Use the lines of best fit to work out the percentage of tin in solder with the lowest melting point.

Solder conducts electricity like a typical metal.

Explain why.

Use knowledge of the properties of metals in your answer.

Look at Fig. 13.3. It shows how the atoms are arranged in pure lead and in solder.

Solder is an example of a formulation.

What name is given to a formulation which is a mixture of metals such as solder?

Suggest whether solder is harder, softer or the same hardness as pure lead.

Explain your answer using your knowledge of the properties of metals.

Aluminium, phosphorus and magnesium are all in Period 3 of the Periodic Table.

Aluminium has an atomic number of 13 and mass number of 27.

Describe the nucleus of an aluminium atom in terms of sub-atomic particles.

What is the overall charge on the nucleus of an atom of aluminium?

Which sub-atomic particles surround the nucleus?

Phosphorus has a higher atomic number and a higher mass number than aluminium.

A student says that phosphorus must be an isotope of aluminium because it has a different number of neutrons.

Is the student correct?

Tick (✓) one box.

Explain your answer.

Phosphorus can react with oxygen to form oxides. One oxide of phosphorus is called phosphorus pentoxide.

Phosphorus pentoxide has the molecular formula P₄O₁₀.

What is the empirical formula of phosphorus pentoxide?

Aluminium oxide and phosphorus pentoxide have different types of bonding.

The boiling point of aluminium oxide is 2977 °C.

The boiling point of phosphorus pentoxide is 360 °C.

What conclusion can you make about the type of bonding in each oxide?

Explain your answers.

The student is given a sample of the metal magnesium and a solution of an unknown nitrate of metal M, MNO₃(aq).

The student does an experiment to identify metal M.

The student weighs the magnesium. Then the student adds the magnesium to the solution of the metal nitrate.

A displacement reaction takes place forming metal M:

The student separates the metal M and then weighs metal M.

Look at the student’s results: Mass of magnesium = 0.729 g Mass of metal M = 6.476 g

Calculate the moles of magnesium used in the experiment.

Calculate the relative atomic mass of metal M.

Give your answer to 3 significant figures.

Use your answer from (d)(ii) and the Periodic Table to identify the metal M.