Ionic bonding & ionic compounds

Sodium chloride is an ionic compound.

Sodium chloride is made from sodium ions, Na +, and chloride ions, C l –. (a)

Fig. 13.1 shows a model for the ionic lattice of sodium chloride.

Complete by writing in the missing sodium ions, Na +, and chloride ions, C l –. Fig. 13.1

Fig. 13.1

What is the formula of sodium chloride?

Sodium chloride can be split up into its elements using electrolysis.

During electrolysis, sodium chloride must be heated until it is a liquid.

The table shows the melting point and boiling point of sodium chloride.

Suggest a temperature that sodium chloride should be heated to so it is a liquid.

Fig. 13.2 shows a diagram for the electrolysis of molten sodium chloride.

Fig. 13.2

What is the name of the piece of equipment, X ?

Name the gas produced at the anode.

A student thinks that the electrodes (anode and cathode) should be inert and made from graphite.

Complete the sentences to explain why the student is correct.

Graphite is reactive / unreactive. It is an electrical conductor / electrical insulator.

Sodium chloride contains 39% sodium.

Calculate the mass of sodium that is produced from the electrolysis of 160 kg of sodium chloride.

Give your answer to 2 significant figures.

* Fig. 13.3 shows the dot and cross diagram for sodium chloride.

Fig. 13.3

Sodium atom Chlorine atom Sodium ion Chloride ion

Explain how sodium and chlorine atoms form sodium and chloride ions.

Use information:

• from Fig. 13.3

• your knowledge of chemical bonding

• ideas about the electron arrangement in the atoms and ions.

Sodium hydroxide, NaOH, and calcium hydroxide, Ca(OH)₂, are ionic compounds that dissolve in water to form alkaline solutions.

Why are solutions of sodium hydroxide and calcium hydroxide called alkalis?

Explain why the formula of sodium hydroxide is NaOH but the formula of calcium hydroxide is Ca(OH)₂.

The electrolysis of a sodium hydroxide solution produces hydrogen at the cathode rather than sodium.

Explain why.

When carbon dioxide is bubbled through a calcium hydroxide solution it turns cloudy white.

This is the equation for the reaction.

Which chemical in the equation turns the solution cloudy white?

What is the alternative name for the calcium hydroxide solution?

The calcium hydroxide solution contains 0.038 g of calcium hydroxide.

Calculate the maximum mass of carbon dioxide that can react with the calcium hydroxide solution.

Give your answer to 2 significant figures.

Relative atomic mass (A_r): H = 1.0 C = 12.0 O = 16.0 Ca = 40.1

Write the formula of the molecules in the box for R to show a balanced reaction.

Write the name and the formula of the compound in solution S.

Name the type of reaction which happens between solutions P and Q.

Which of the solutions in the diagram shows a strong acid?

Tick (✓) one box.

Give two reasons for your answer.

A student dissolves 2 g of a strong acid in 250 cm³ of water. (e)

Calculate the concentration of the solution formed in g / dm³.

Concentration of the solution =........ g / dm³

Sodium sulfite contains Na⁺ ions and SO^2– ions. 8₃

What is the formula of sodium sulfite?

A NaSO₃

B Na(SO₃)₂

C Na₂SO₃

D Na₂(SO₃)₂

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.

Atoms are made from protons, neutrons and electrons.

The table shows the relative mass and relative charge of a proton, neutron and electron.

Complete the table.

Write your answers in the three boxes in the table.

An atom of helium contains:

• 2 protons

• 2 neutrons

• 2 electrons.

Draw a labelled diagram to show the arrangement of protons, neutrons and electrons in an atom of helium.

Which two elements are in Group 1 of the Periodic Table?

Which element is in Period 4 of the Periodic Table?

Which element has a mass number of 12?

Which two elements are isotopes?

Which element forms an ion with a 2+ charge?

Aluminium forms an Al³⁺ ion and chlorine forms a Cl^– ion. (e)

Three students write down the formula of aluminium chloride.

Student A: A l C l

Student B: Al Cl₃

Student C: Al₃Cl

Which student is correct?

Explain your answer.

The reaction between solid citric acid and sodium hydrogen carbonate solution is an endothermic reaction.

A student investigates the temperature change for the reaction.

The diagram shows the equipment the student uses.

50 cm³ of sodium hydrogen carbonate solution

The student adds 0.65 g of solid citric acid to an excess of sodium hydrogen carbonate solution.

The student measures the temperature change. The temperature change is 3.5 °C.

How does a temperature change show that a reaction is endothermic?

How should the student have written the temperature change to show that this reaction is endothermic?

Describe how the student performed the experiment so that they could calculate the temperature change.

The student repeats the experiment using a different mass of citric acid. This time the student measures a larger temperature change.

The temperature change is 10.0 °C.

If 0.65 g of citric acid gives a temperature change of 3.5 °C, calculate the mass of citric acid, in milligrams, that gives a 10.0 °C temperature change.

1 g = 1000 mg

Give your answer to 3 significant figures.

When the student washed out the plastic cup at the end of the second experiment they saw some excess solid left.

Explain how this affected the student’s result and describe how the student could have improved their experiment.

Citric acid and sodium hydrogen carbonate react to form sodium citrate.

Sodium citrate contains sodium ions, Na⁺, and citrate ions, C₆H₅O₇^3–.

Write the formula of sodium citrate.

The reaction between solid citric acid and sodium hydrogen carbonate solution is an endothermic reaction.

A student investigates the temperature change for the reaction.

The diagram shows the equipment the student uses.

50 cm³ of sodium hydrogen carbonate solution

The student adds 0.65 g of solid citric acid to an excess of sodium hydrogen carbonate solution.

The student measures the temperature change. The temperature change is 3.5 °C.

How does a temperature change show that a reaction is endothermic?

How should the student have written the temperature change to show that this reaction is endothermic?

Describe how the student performed the experiment so that they could calculate the temperature change.

The student repeats the experiment using a different mass of citric acid. This time the student measures a larger temperature change.

The temperature change is 10.0 °C.

If 0.65 g of citric acid gives a temperature change of 3.5 °C, calculate the mass of citric acid, in milligrams, that gives a 10.0 °C temperature change.

1 g = 1000 mg

Give your answer to 3 significant figures.

When the student washed out the plastic cup at the end of the second experiment they saw some excess solid left.

Explain how this affected the student’s result and describe how the student could have improved their experiment.

Citric acid and sodium hydrogen carbonate react to form sodium citrate.

Sodium citrate contains sodium ions, Na⁺, and citrate ions, C₆H₅O₇^3–.

Write the formula of sodium citrate.

This question is about compounds of magnesium.

Magnesium hydroxide contains magnesium ions, Mg²⁺, and hydroxide ions, OH^–. (a)

Write the formula of magnesium hydroxide.

Magnesium carbonate, MgCO₃, reacts with dilute hydrochloric acid, HCl.

Magnesium chloride, MgCl₂, water and carbon dioxide are made.

Write the balanced symbol equation for the reaction.

A compound of magnesium contains an unknown element, X.

X is an element found in Group 7 of the Periodic Table.

The compound has the formula MgX₂.

The relative formula mass of the MgX₂ is 184.1.

Calculate the relative atomic mass of X. A_r Mg = 24.3