Ionic bonding and ionic compounds

Calcium phosphate is an ionic compound with the formula Ca₃(PO₄)₂

What is the total number of atoms in the formula Ca₃(PO₄)₂?

What are the correct charges on the ions in calcium phosphate?

Calculate the relative formula mass (M_r) of Ca₃(PO₄)₂

M_r of Ca₃(PO₄)₂ =_........

Calculate the percentage by mass of calcium in calcium phosphate.

Calcium hydroxide can react with phosphoric acid to form calcium phosphate.

Complete the equation for this reaction.

This question is about metals and metal compounds.

The method used to extract a metal depends on the reactivity of the metal.

Explain which method is used to extract sodium metal from sodium chloride.

The diagram shows the arrangement of particles in a pure metal.

Explain why pure metals are soft.

The diagram shows the electronic structure of an atom of sodium and an atom of oxygen.

Describe, in terms of electrons, what happens when sodium reacts with oxygen.

The table shows the melting points of sodium and sodium oxide.

Explain why sodium and sodium oxide have different melting points.

In your answer you should refer to:

• the structures of sodium and sodium oxide

• the forces between the particles

This question is about ionic and covalent compounds.

The table gives the formulae of some positive ions, some negative ions and some compounds containing these ions.

Complete the table by giving the three missing formulae.

Give the name of the compound with the formula Al₂(SO₄)₃

The diagram shows the arrangement of electrons in an atom of magnesium and an atom of chlorine.

Describe, in terms of electrons, what happens when magnesium atoms and chlorine atoms form magnesium chloride.

Complete the dot-and-cross diagram to show the outer shell electrons in a molecule of ammonia.

Describe the forces of attraction in a covalent bond.

The table shows the composition of five species that are either atoms or ions.

Use the table to answer these questions.

You may use each letter once, more than once, or not at all.

Give the letter of the species that is a negative ion.

Give the letter of the species that has a full outer shell of electrons.

Give the letter of the species that has an atomic number equal to its mass number.

Explain why species B and C are atoms of the same element with identical chemical properties.

A proton has a mass of 1.672610^–24g.

A neutron has a mass of 1.674010^–24g.

Calculate the mass, in grams, of the nucleus of an atom of species C.

This question is about atomic structure.

The table shows the number of protons, neutrons and electrons in five species, V, W, X, Y and Z.

The letters represent the species but are not symbols from the Periodic Table.

Choose letters from the table to answer these questions.

Each letter may be used once, more than once or not at all.

Which species is an atom?

Which species is an ion with a positive charge?

Which species is an ion with a 3− charge?

State what is meant by the term atomic number.

State what is meant by the term mass number.

The table shows the formulae of some positive and negative ions, and the formulae of some compounds containing these ions.

Complete the table by giving the formulae of the missing compounds.

Give the name of the compound with the formula ZnSO₄

Hydrogen chloride and magnesium chloride have different types of bonding and have different structures.

Complete the dot-and-cross diagram to show the outer shell electrons in a molecule of hydrogen chloride.

H C l

The diagram shows the electronic configuration of a magnesium atom and of a chlorine atom.

Draw the electronic configuration of a magnesium ion and of a chloride ion in the boxes.

Show the charge on each ion.

Explain why magnesium chloride has a much higher melting point than hydrogen chloride.

Refer to structure and bonding in your answer.

This question is about sulfur.

The diagram represents the electronic configuration of an atom of sulfur.

Which period of the Periodic Table contains sulfur?

What is the charge on a sulfide ion?

When a mixture of sulfur and zinc is heated to a high temperature a reaction occurs, forming the compound zinc sulfide, ZnS

Give a reason why the mixture of sulfur and zinc needs heating before a reaction occurs.

Calculate the relative formula mass (M_r) of zinc sulfide.

[for Zn, A_r = 65 for S, A_r = 32]

This question is about Group 7, the halogens.

What is the total number of electrons in one fluorine atom?

What is the charge on a bromide ion?

Which of these describes the element iodine at room temperature?

When a halogen is added to a solution containing halide ions, a displacement reaction may occur.

The table shows whether a reaction occurs.

Using information from the table, explain the order of reactivity of the three halogens.

The diagram represents an atom of an element.

What is the particle labelled W?

An atom of this element contains 13 neutrons.

What is the mass number of this element?

State why atoms have no overall charge.

What is the charge on the ion usually formed from this element?

There are two isotopes of the element lithium.

State why both isotopes react in the same way.

A sample of lithium contains 7.60%₃⁶Li and 92.4%⁷₃Li

Calculate the relative atomic mass, A_r, of this sample of lithium.

Give your answer to two decimal places.

This question is about lithium and some of its compounds.

A small piece of lithium is added to a trough containing water.

The lithium floats on the surface of the water and a vigorous reaction occurs.

Give two other observations when lithium reacts with water.

A few drops of methyl orange are added to the solution in the trough.

Explain the final colour of the solution.

An unlabelled bottle containing a white powder is found in a laboratory.

Describe tests to show that the white powder in the bottle is lithium carbonate.

Lithium carbonate has ionic bonding.

State what is meant by the term ionic bonding.

When solutions of lead(II) nitrate and potassium chloride are mixed, a precipitate of lead(II) chloride forms.

Complete the equation for the reaction by adding the state symbols.

Give the formula of each ion in lead(II) nitrate.

lead ion

nitrate ion

Calculate the relative formula mass (M_r) of lead(II) nitrate, Pb(NO₃)₂

A student investigates the height of the precipitate formed when lead(II) nitrate solution is added to potassium chloride solution.

This is the student’s method.

Step 1&$pour=NRKM cm³ of potassium chloride solution into a boiling tube

Step 2&$~dd=OKM cm³ of lead(II) nitrate solution and allow the precipitate to settle

Step 3 measure the height of the precipitate

Repeat steps 2 and 3 until a total of 14.0 cm³ of lead(II) nitrate solution has been added.

The table shows the student’s results.

Plot the results on the grid.

Draw a circle around the anomalous result.

Draw a line of best fit through the first four points and another line of best fit through the last three points. Make sure that the lines cross.

Volume of lead(II) nitrate in cm³

Give two possible mistakes the student could have made to cause the anomalous result.

State why the first line of best fit should pass through the origin.

Use your graph to determine the volume of lead(II) nitrate solution needed to react completely with 15.0 cm³ of potassium chloride solution.

This question is about ionic compounds.

Calcium nitrate has the formula Ca(NO₃)₂

Give the formula of each ion in calcium nitrate.

calcium ion

nitrate ion

Explain why calcium nitrate has a high melting point.

Refer to structure and bonding in your answer.

Calcium nitrate decomposes when heated.

Complete the chemical equation for the decomposition of calcium nitrate.

A student has four unlabelled beakers, each containing a colourless solution of a different salt.

These are the four salt solutions.

• calcium bromide

• calcium chloride

• sodium chloride

• sodium sulfate

Describe a series of tests to identify each solution.

Do not refer to safety precautions in your answer.

Use the Periodic Table to help you answer this question.

Name the element with atomic number 14.

Name the element in Group 2 and Period 3.

Name an element that is a liquid at room temperature.

Give the electronic configuration of an atom of phosphorus.

Give the formula of sodium sulfide.

Explain, in terms of electron configuration, why neon is unreactive.

This question is about ionic compounds.

The table gives the formulae of some positive and negative ions, and the formulae of some compounds containing these ions.

Complete the table by giving the missing formulae.

Give the name of the compound with the formula MgO

Calculate the relative formula mass (M_r) of Na₃N

[for Na, A_r = 23 for N, A_r = 14]

The diagram shows the arrangement of electrons in atoms of lithium and in an atom of oxygen.

Describe the changes in the electron configurations of lithium and oxygen when these atoms form lithium oxide, Li₂O

Lithium oxide has a giant ionic structure.

Explain why lithium oxide has a high melting point.

The diagram shows the electronic configuration of an atom of an element.

Complete the table by giving the missing information.

The table gives information about four different species, W, X, Y and Z.

Give the mass number of W.

Give a reason why X has a 3+ charge.

Explain why Y and Z are isotopes of the same element.

This question is about the element phosphorus and some of its compounds.

The atomic number of phosphorus is 15

Give the electronic configuration of an atom of phosphorus.

Calcium phosphide is an ionic compound used in pest control.

The formula of a calcium ion is Ca²⁺

Explain why the formula of calcium phosphide is Ca₃P₂

Calcium phosphide can be produced by heating calcium phosphate with carbon.

Complete the equation for the reaction.

Explain the role of carbon in the reaction.

Calcium phosphide reacts with water to form calcium hydroxide and phosphine, PH₃

Give a chemical equation for this reaction.

Explain why calcium phosphide has a high melting point.

You should refer to structure and bonding in your answer.

The diagram shows the electronic configuration of an atom of an element.

Name the part of the atom that contains the protons and neutrons.

Give the number of protons in this atom.

Give the number of the group that contains this element.

Give the number of the period that contains this element.

Give the charge on the ion formed from this atom.

This question is about the oxides of lead.

Yellow lead oxide (PbO) can be reacted with hydrogen to produce lead.

Complete the equation for the reaction by adding the missing state symbols.

What is the charge on the lead ion in PbO?

Explain why the reaction of yellow lead oxide with hydrogen is a redox reaction.

Describe a physical test to show that the water produced in this reaction is pure.

When red lead oxide (Pb₃O₄) is heated, yellow lead oxide forms.

The equation for the reaction is

A scientist heats a known mass of red lead oxide in a crucible in a fume cupboard.

The scientist leaves the crucible to cool, then records the total mass of the crucible and its contents.

Describe what the scientist should do next to make sure that all the red lead oxide has reacted.

The red lead oxide used in the reaction has a mass of 5.48 g.

Calculate the maximum mass of yellow lead oxide that could form.

[M_r of Pb₃O₄ = 685 M_r of PbO = 223]

A student investigates how the electrical conductivity changes as dilute sulfuric acid is added to barium hydroxide solution.

This is the student’s method.

Step 1 =$~dd=RMKM cm³ of barium hydroxide solution to a beaker

Step 2 measure the electrical conductivity of the solution

Step 3 =$~dd=NMKM cm³ of dilute sulfuric acid to the beaker

Step 4 stir the mixture

Step 5 measure the electrical conductivity of the mixture

Step 6 repeat steps 3 to 5 until a total of 100 cm3³ of dilute sulfuric acid has been added

The table shows the student’s results.

Name a piece of apparatus the student could use to add 10.0 cm³ of dilute sulfuric acid to the beaker.

Plot the student’s results.

Ignoring the anomalous result, draw two lines of best fit, making sure that the two lines cross.

Total volume of acid added in cm³

Give the trend shown on the graph for the first 50 cm³ of acid added.

Suggest a mistake the student could have made to cause the anomalous result.

This is the equation for the reaction.

When 50 cm³ of dilute sulfuric acid have been added, only barium sulfate and water are present in the mixture.

Explain why this mixture does not conduct electricity. Refer to the type of bonding in barium sulfate and in water in your answer.

Name a technique the student could use to separate barium sulfate from the mixture after 100 cm³ of dilute sulfuric acid has been added.

This question is about ammonia and ammonium compounds.

Ammonia (NH₃) is a simple covalent molecule.

Draw a dot-and-cross diagram to show the bonding in a molecule of ammonia.

The table shows the names and formulae of some ammonium compounds.

Complete the table by giving the missing information.

When ammonia reacts with sulfuric acid, ammonium sulfate is formed.

Write a chemical equation for this reaction.

Describe a test for ammonium ions.

The table gives some information about ammonia and ammonium compounds.

Calculate the percentage of nitrogen in ammonium nitrate.

[M_r of NH₄NO₃ = 80]

Fertilisers add nitrogen to the soil to help plants grow.

Ammonia and ammonium sulfate can both be used as fertilisers.

Discuss the advantages and disadvantages of using each of these compounds as fertilisers.

Use information from the table in your answer.

[pH of rainwater is approximately 5.6]

This question is about magnesium and magnesium compounds.

Magnesium burns in oxygen to form magnesium oxide.

State two observations that would be seen during the reaction.

The diagram shows the electron configurations of a magnesium atom and an oxygen atom.

Describe the changes in the electronic configurations when magnesium reacts with oxygen to form the ionic compound magnesium oxide, MgO

Magnesium can be produced by the electrolysis of molten magnesium chloride.

State why magnesium cannot be produced by heating magnesium oxide with carbon.

Explain the different ways that magnesium and magnesium chloride conduct electricity.

magnesium

magnesium chloride

During the electrolysis of molten magnesium chloride, magnesium is formed at the negative electrode.

The ionic half‑equation for the reaction is

State why this is a reduction reaction.

Write an ionic half‑equation for the formation of chlorine at the positive electrode.

The diagram represents the structure of copper metal.

Explain three properties of copper that make it a suitable metal to use in electrical wiring.

The diagram shows the electrolysis of copper(II) sulfate solution, using graphite electrodes.

Copper forms at the negative electrode and oxygen forms at the positive electrode.

Give the formula of the copper ion and the formula of the sulfate ion in copper(II) sulfate.

copper ion

sulfate ion

State what would be seen at the positive electrode.

Give a test for oxygen.

Give an ionic half‑equation for the formation of oxygen at the positive electrode.

Suggest why the copper(II) sulfate solution contains some OH^– ions.

This question is about sodium oxide, Na₂O

The diagram shows the electronic configuration of atoms of sodium and oxygen.

Describe the changes in the electronic configuration of the atoms of sodium and oxygen to form the ions in sodium oxide.

Calculate the relative formula mass (M_r) of sodium oxide, Na₂O, using information from the Periodic Table.

Explain why solid sodium oxide does not conduct electricity.

Give a test to show that sodium oxide contains sodium ions.

When sodium oxide is heated it reacts to form sodium metal and sodium peroxide, Na₂O₂

Complete the equation for this reaction.

This question is about ionic compounds.

State the formula of the cation and the anion in magnesium sulfate.

The diagram shows the electronic configuration of a potassium atom and an oxygen atom.

Potassium oxide (K₂O) is an ionic compound.

Draw the electronic configuration of a potassium ion and an oxide ion.

Show the charge on each ion.

A sample of solid potassium oxide is added to water.

A reaction occurs and a colourless solution forms.

When a few drops of phenolphthalein indicator are added to the solution it turns pink.

Identify the ion responsible for the colour change.

Give a chemical equation for the reaction between potassium oxide and water.

Explain why ionic compounds conduct electricity when molten or in aqueous solution, but not when in the solid state.

The diagram shows the apparatus a teacher uses to demonstrate the electrolysis of a concentrated aqueous solution of sodium chloride.

During the electrolysis two gases, X and Y, are formed. One of the gases produces a squeaky pop when tested with a lighted splint.

Use ionic half‑equations to identify X and Y.

The formation of ions and covalent bonds involves electrons.

The table gives the electronic configurations of atoms of hydrogen, lithium and chlorine.

Describe the different roles of electrons in the formation of

ions in lithium chloride

covalent bonds in hydrogen chloride

Explain why lithium chloride has a higher melting point than hydrogen chloride.

Refer to structure and bonding in your answer.

This question is about elements in Group 7 and their compounds.

The table gives information about some of these elements.

Predict the colour of fluorine at room temperature.

How many of the elements in the table are liquids at room temperature (20C)?

The element astatine is below iodine in Group 7.

Predict the formula of a molecule of astatine.

Sea water contains bromide ions.

Bromine can be obtained by bubbling chlorine through a sample of sea water.

The ionic equation for the reaction is

Explain which species acts as an oxidising agent in this reaction.

The reaction occurs because chlorine is more reactive than bromine.

Bromine is below chlorine in Group 7.

Explain the decrease in reactivity from chlorine to bromine.

Elements in Group 7 react with elements in Group 1 to form ionic compounds.

Which pair of ions both have the electronic configuration 2.8.8?

This question is about chemical elements.

Use the Periodic Table to help you answer this question.

Identify the element with atomic number 5

Give the symbol of a metallic element in Period 3

Identify the element whose atoms contain 14 protons.

Identify the element whose atoms have the electronic configuration 2.5

Give the name of the compound formed between oxygen and the element with atomic number 13

The position of an element in the Periodic Table can be used to predict its properties.

Which group contains elements that are all unreactive?

Which of these is the least reactive element in Group 1?

Sodium hydroxide dissolves in water, forming a strongly alkaline solution.

Ammonia dissolves in water, forming a slightly less alkaline solution.

Identify the ion that makes the sodium hydroxide solution alkaline.

What is a possible pH of ammonia solution?

When ammonia solution reacts with sulfuric acid, a neutralisation reaction occurs and ammonium sulfate forms.

How does the sulfuric acid act in this reaction?

The diagram shows a beaker containing some ammonia solution and a few drops of phenolphthalein indicator.

Dilute sulfuric acid is added to the beaker until it is in excess.

What are the colours of the phenolphthalein indicator before and after adding excess sulfuric acid?

Ammonium sulfate is used by gardeners as a fertiliser because it contains nitrogen.

Explain why the chemical formula of ammonium sulfate is (NH₄)₂SO₄

Refer to the charges on the ions in your answer.

Calculate the relative formula mass of ammonium sulfate, (NH₄)₂SO₄

Calculate the mass, in grams, of nitrogen in 1.0 kg of ammonium sulfate.

Thallium, Tl, is an element in Group 3 and Period 6 of the Periodic Table.

The atomic number of thallium is 81

How many electrons are there in the outer shell of an atom of thallium?

A thallium ion has a charge of 3+

How many electrons are there in this thallium ion?

A sample of thallium contains two isotopes.

The table shows the mass number and percentage abundance of each isotope in the sample.

Give the number of protons and the number of neutrons in one atom of the thallium-205 isotope.

number of protons_........

number of neutrons_........

Calculate the relative atomic mass of this sample of thallium.

Give your answer to one decimal place.

This question is about some of the alkali metals and their compounds.

When a teacher drops a small piece of sodium into a trough of cold water, she observes bubbles of gas.

Give two other observations that would be made when sodium reacts with cold water.

Lithium reacts with fluorine to form the compound lithium fluoride.

Give a chemical equation for this reaction.

Give a test to show that lithium fluoride contains lithium ions.

Draw diagrams to show the arrangement of the electrons in a lithium ion and in a fluoride ion.

Include the charge on each ion.

lithium ion
fluoride ion

The table shows the electronic configurations of sodium and potassium.

Explain, in terms of their electronic configurations, why potassium is more reactive than sodium.

The diagram shows the particles in the atom of an element.

Particle Y is a proton.

What is particle Z?

Which of these has the smallest mass?

What is the mass number of this atom?

What is the atomic number of this atom?

Identify the element that contains this atom.

State what is formed when this atom loses its outer shell electrons.

The Group 7 elements are called halogens.

Halogens form compounds called halides.

Three of the halogens are represented by the formulae X₂, Y₂ and Z₂

Solutions of these halogens are added separately to solutions of sodium halides, NaX, NaY and NaZ.

The table shows whether or not a reaction occurs.

Use the information in the table to deduce the order of reactivity of the halogens X₂, Y₂ and Z₂

An aqueous solution of halogen Y₂ is orange.

This solution is decolourised when it reacts with an alkene.

Deduce the identity of halogen Y₂

The table shows some physical properties of the halogens.

Complete the table by predicting a boiling point for chlorine, the state of fluorine at room temperature and the colour of astatine.

Why do the halogens have similar chemical properties?

A teacher uses this apparatus to demonstrate the reaction between chlorine gas and iron wool. The teacher does the reaction in a fume cupboard.

Suggest why the teacher does the reaction in a fume cupboard.

The product of the reaction between iron and chlorine is iron(III) chloride.

The ions in iron(III) chloride are Fe³⁺ and Cl⁻

Use this information to give the chemical equation for this reaction.

This question is about ammonium chloride.

Give the formula of the ammonium ion.

Describe a test to show that ammonium chloride contains ammonium ions.

The equation shows the thermal decomposition of ammonium chloride.

State what the symbol indicates about this reaction.

The diagram shows the formation of ammonium chloride in a glass tube.

cotton wool soaked in cotton wool soaked in concentrated hydrochloric acid
ammonium chloride concentrated ammonia solution

Explain how the mean speed of ammonia molecules compares with the mean speed of hydrogen chloride molecules.

Gas particles travel very quickly.

Give two reasons why it takes several minutes for the ammonium chloride to form.

This question is about ionic compounds.

The table shows the formulae of some positive and negative ions, and the formulae of some compounds containing these ions.

Complete the table by giving the three missing formulae.

Give the name of the compound with the formula NH₄NO₃

Sodium oxide, Na₂O, is an ionic compound.

The sodium and oxide ions are held together by ionic bonds.

State the meaning of the term ionic bond.

The diagram shows the arrangement of the electrons in a sodium atom and in an oxygen atom.

Draw diagrams in the boxes to show the arrangement of the electrons in the ions of sodium oxide.

Include the charges on the ions.

The diagram shows the arrangement of electrons in an atom of calcium and in an atom of chlorine.

Describe, in terms of electrons, what happens when calcium reacts with chlorine to form the ionic compound calcium chloride, CaCl₂

Describe tests to show that an aqueous solution of calcium chloride contains calcium ions and chloride ions.

Solid calcium chloride does not conduct electricity. Aqueous solutions of calcium chloride do conduct electricity.

A student uses this method to investigate how the conductivity of a solution changes when calcium chloride is dissolved in pure water.

Step 1 add 100 cm³ of pure water to a beaker

Step 2 add one spatula of solid calcium chloride to the beaker

Step 3 stir the solution

Step 4 measure the conductivity of the solution

Step 5 repeat until nine spatulas of solid calcium chloride have been added

The table shows the student’s results.

Plot the results on the grid and draw two straight lines of best fit.

Ignore the anomalous result.

State the trend shown on the graph for the first six spatulas of calcium chloride.

Suggest an error the student could have made to cause the anomalous result.

Describe another way to make solid calcium chloride conduct electricity.

This question is about the halogens and their compounds.

The table gives the colour and physical state at room temperature of the halogens.

Complete the table by predicting the colour of astatine and the physical state of fluorine at room temperature.

Chlorine gas is bubbled into a colourless solution of potassium bromide.

Explain why the solution turns orange.

Potassium bromide is an ionic compound.

Draw diagrams to show the outer electrons in a potassium ion and in a bromide ion.

Include the charges on the ions.

A student sets up a circuit to test the electrical conductivity of water, solid sodium chloride and aqueous sodium chloride.

The table shows the student’s results.

Explain these results, with reference to the structure and bonding of the substances.

A concentrated aqueous solution of sodium chloride is electrolysed using graphite electrodes.

Chlorine is formed at the positive electrode (anode).

Give an ionic half‑equation for the formation of chlorine at the positive electrode.

State why this ionic half‑equation represents an oxidation reaction.

Which substance is formed at the negative electrode (cathode)?