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2.2 Bonding structure - How bonds relate to structure - Standard demand – Questions

Q1.This question is about structure and bonding.

(a) Oxygen is in Group 6.

The diagram shows the outer shells in an oxygen molecule.

Complete the dot and cross diagram.

You should show only the electrons in the outer shell.

(2)

(b) Oxygen forms many compounds.

Which two compounds of oxygen are small molecules?

Tick two boxes.

Carbon dioxide

Magnesium oxide

Potassium oxide

Silicon dioxide

Water

(2)

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(c) Explain why metals conduct electricity.

Refer to structure and bonding in your answer.

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(Total 8 marks)

Q2.This question is about copper and its compounds.

(a) The table shows information about bioleaching and phytomining.

Bioleaching and phytomining are used to extract copper from low grade ores.

Bioleaching Phytomining

Metal extracted from

Waste from quarrying Contaminated ground

Speed of process Very slow

Slow, made more efficient using quick-growing plants

Pollution

Produces a solution of toxic chemicals which may run off into rivers

Takes a long time to stop the process if river pollution occurs

Involves combustion of plants but decontaminates polluted ground

Compare phytomining and bioleaching.

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Use the information in the table.

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(b) Describe how copper sulfate solution is obtained from the plants used in phytomining.

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(c) Copper is displaced from a solution of copper sulfate using iron.

Write a balanced symbol equation for this reaction.

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(d) How does this displacement reaction take place?

Tick one box.

Electron sharing

Electron transfer

Proton transfer

(1)

(e) Describe how copper conducts electricity.

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(f) Suggest how anhydrous copper sulfate is used to test for water.

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(Total 13 marks)

Q3.Three substances are all solid at room temperature.

The table describes tests and the result of each test on the three substances.

SubstanceEffect of large force applied

Effect of heating gently at first, then strongly

Effect of passing electricity through solid

Effect of passing electricity through liquid

A Breaks into many pieces

Easily melts and then boils

Does not conduct

Does not conduct

B Breaks into many pieces No change Does not

conduct Conducts

C Becomes thinner No change Conducts Conducts

(a) The covalent bonds in the molecules are not overcome when substance A is heated.

What forces are overcome when substance A melts?

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(b) What could substance A be?

Tick one box.

Graphite

Iron

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Sodium chloride

Sulfur

(1)

(c) Suggest why substance B conducts electricity as a liquid but does not conduct electricity as a solid.

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(d) Suggest why substance C becomes thinner when a large force is applied.

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(e) What could substance C be?

Tick one box.

Copper

Diamond

Iodine

Magnesium oxide

(1)(Total 8 marks)

Q4.This question is about beryllium.

(a) Beryllium is in Group 2.

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What does this tell you about the electronic structure of beryllium?

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Beryllium is found in beryllium aluminium silicate.

The formula of beryllium aluminium silicate is Be3Al2(SiO3)6

(b) What is the ratio of atoms of each element in beryllium aluminium silicate?

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Ratio of Be : Al : Si : O = ___ : ___ : ___ : ___ (1)

(c) What percentage by mass of beryllium is in beryllium aluminium silicate?

Give your answer to 2 significant figures.

Relative atomic mass (Ar) of Be = 9

Relative formula mass (Mr) of Be3Al2(SiO3)6 = 537

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Percentage of beryllium = ____________________ %(2)

Beryllium can be extracted from beryllium chloride.

Beryllium chloride (BeCl2) is heated with potassium to produce beryllium and potassium chloride (KCl).

(d) Complete the equation for the reaction.

Your equation should be balanced.

BeCl2 + _____ → _____ + _____(2)

(e) Explain why beryllium is produced when potassium is heated with beryllium chloride.

You should refer to reactivity in your answer.

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(f) Describe a test to show that beryllium is a metal.

Give the result of the test.

Test _______________________________________________________________

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Result _____________________________________________________________

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(Total 10 marks)

Q5.Read the information

Graphene

Scientists have made a new substance called graphene.The bonding and structure of graphene are similar to graphite.

Graphene is made of a single layer of the same atoms as graphite.

Graphene Graphite

Use the information above and your knowledge of graphite to answer the questions.

(a) This part of the question is about graphene.

Choose the correct answer to complete each sentence.

(i) ionic covalent metallic

The bonds between the atoms in graphene are _______________________(1)

(ii) chromium carbon chlorine

Graphene is made of __________________________ atoms.(1)

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(iii) 2 3 4

In graphene each atom bonds to ___________ other atoms.(1)

(b) This part of the question is about graphite.

Graphite is used in pencils.

Explain why. Use the diagrams to help you.

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(Total 5 marks)

Q6.(a) Magnesium metal is shaped to make magnesium ribbon.

Explain why metals can be shaped.

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(b) Magnesium sulfate is a salt of magnesium.

It can be prepared by the reaction of magnesium metal with an acid. The equation for the reaction of magnesium with this acid is:

Mg(s) + H2SO4(aq) → MgSO4(aq) + H2(g)

(i) Name the acid used to make magnesium sulfate.

___________________________________ acid(1)

(ii) Use the equation to help you to describe what you would observe when magnesium reacts with the acid.

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(iii) The magnesium sulfate is in solution.

How could you obtain solid magnesium sulfate from this solution?

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(Total 6 marks)

Q7.Lead compounds have been used for thousands of years as colours in paint.

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Johannes Vermeer [Public domain], via Wikimedia Commons

(a) A sample of a red oxide used in paint was found to contain 6.21 g of lead and 0.64 g of oxygen.

Calculate the empirical (simplest) formula of this compound.

You must show all your working to gain full marks.

Relative atomic masses: O = 16; Pb = 207.

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(b) A problem with lead compounds is that they slowly react with hydrogen sulfide in the air. This produces lead sulfide which is black.

(i) Hydrogen sulfide has the formula H2S. The bonding in a molecule of hydrogen sulfide can be represented as:

H–S–H

Complete the diagram below to show the arrangement of the outer electrons of the hydrogen and sulfur atoms in hydrogen sulfide.Use dots (●) and crosses (x) to represent the electrons.You need only show the outer shell electrons.(Atomic numbers: H = 1; S = 16.)

(1)

(ii) Hydrogen sulfide has a low boiling point.

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Explain why.

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(iii) Lead white is also used in paint. The white colour slowly darkens when lead sulfide is produced.

The painting can be restored with hydrogen peroxide. This converts the black lead sulfide into white lead sulfate.

Balance the equation for the reaction between lead sulfide and hydrogen peroxide (H2O2).

PbS(s) + ______H2O2(aq) → PbSO4(s) + 4H2O(l)

(1)(Total 8 marks)

Q8.(a) The table gives information about two isotopes of hydrogen, hydrogen-1 and

hydrogen-2.

Hydrogen-1 Hydrogen-2

Atomic number 1 1

Mass number 1 2

An atom of hydrogen-1 is represented as:

Show how an atom of hydrogen-2 is represented.

(1)

(b) (i) Calculate the relative formula mass (Mr) of water, H2O

Relative atomic masses: H = 1; O = 16.

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Relative formula mass (Mr ) = ______________________(1)

(ii) Simple molecules like water have low boiling points.

Explain why, in terms of molecules.

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(c) Molecules of heavy water contain two atoms of hydrogen-2 instead of two atoms of hydrogen-1.

Explain why a molecule of heavy water has more mass than a normal water molecule.You should refer to the particles in the nucleus of the two different hydrogen atoms in your answer.

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(Total 6 marks)

Q9.Aluminium has many uses because of its low density, good electrical conductivity, flexibility and resistance to corrosion.

The main steps in the extraction of aluminium are shown in the flow chart.

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(a) Use the information in the flow chart to suggest the benefits of recycling aluminium.

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(b) Pure aluminium is rarely used for the construction of large objects. Small amounts of other metals are usually mixed with aluminium.

Explain why.

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(Total 5 marks)

Q10.Bricks made from silica (silicon dioxide) are used to line furnaces that operate at high temperatures.

Part of the structure of silica is shown in the diagram.

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Suggest and explain why silica is used to make bricks for high-temperature furnaces. In your answer, you should refer to the structure of, and bonding in, silica.

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Q11.Aluminium is a useful metal.

(a) The atomic number (proton number) of aluminium is 13.

Complete the diagram to show the electronic structure of an aluminium atom.Use crosses (x) to represent the electrons.

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(1)

(b) Aluminium is used as the electrical conductor for overhead power cables.

Explain why metals are good conductors of electricity.

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(Total 3 marks)

Q12.Many everyday items are made from iron.

(a) Haematite is an ore of iron. Haematite contains iron oxide, Fe2O3.

(i) What is the meaning of the term ore?

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(ii) Iron can be produced by reacting iron oxide with carbon in a blast furnace.

What type of reaction produces the iron?

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(iii) The word equation for this reaction is:

iron oxide + carbon → iron + carbon dioxide

Complete and balance the symbol equation for this reaction.

___Fe2O3 + ___C → __________ + __________(2)

(b) Pure iron is relatively soft and not very strong.

The iron from the blast furnace is very hard and brittle. It contains about 4% carbon and is used as cast iron.

Explain the differences in the properties of pure iron and cast iron by referring to the diagrams.

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(c) The diagram shows the way in which iron is extracted, used and recycled.

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Explain why the recycling of iron is necessary for sustainable development.

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(Total 10 marks)

Q13.Hydrogen chloride (HCl) can be made by the reaction of hydrogen (H2) with chlorine (Cl2).

(a) The diagrams represent molecules of hydrogen and chlorine.

Draw a similar diagram to represent a molecule of hydrogen chloride (HCl).You need show only the outer energy level (shell) electrons.

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(1)

(b) The word equation for the reaction of hydrogen with chlorine is shown below.

hydrogen + chlorine → hydrogen chloride

Write a balanced symbol equation for this reaction.

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(c) Hydrogen chloride gas reacts with magnesium to form the ionic compound called magnesium chloride. Use the table of ions on the Data Sheet to help you to write the formula of magnesium chloride.

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(d) Why does magnesium chloride have a much higher melting point than hydrogen chloride?

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(Total 6 marks)

Q14.The hydrogen halides (hydrogen fluoride, hydrogen chloride, hydrogen bromide and hydrogen iodide) are important chemicals.

The diagram below represents a molecule of hydrogen chloride.

(i) What type of particles are represented by the crosses (X)?

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(ii) What type of chemical bond holds the atoms in this molecule together?

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(iii) Would you expect hydrogen chloride to be a gas, a liquid or a solid, at room temperature and pressure? Explain your answer.

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(Total 5 marks)

Q15.The chart below shows the metals which are present in a coin.

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(a) Identify the alloy used to make this coin.

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(b) The mass of the coin is 2.5 g.Calculate the mass of copper in this coin.

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(c) Suggest what properties would make an alloy suitable for making a coin.

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(Total 6 marks)

Q16.Read the following information about an element X.

The element X melts above 600°C. It conducts electricity at room temperature. It burns in oxygen to form an oxide. When the oxide is mixed with water it turns Universal Indicator blue.

The oxide of X is a white solid at room temperature. It has the formula XO and contains the ion X2+.

The element X reacts with chlorine to form a chloride with a high melting point. The chloride conducts electricity when molten and it is soluble in water.

(a) From the information give three pieces of evidence which suggest that X is a metal.

1. _________________________________________________________________

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2. _________________________________________________________________

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3. _________________________________________________________________

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(b) In which Group of the Periodic Table should X be placed? Give a reason for your answer.

Group _____________________________________________________________

Reason ____________________________________________________________

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(c) Predict the formula for the chloride of X. _________________________________(1)

(Total 6 marks)

Q17.The diagram shows a model of part of the giant lattice of a metal.

(a) Name particles X and Y.

X ___________________________

Y ___________________________(2)

(b) Explain, in terms of the giant structure above, why is it possible to bend a piece of metal.

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(Total 4 marks)

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Q18.Electrons, neutrons and protons are sub-atomic particles.

(a) Complete the six spaces in the following table.

Name of sub-atomic particle

Relative mass Relative charge

____________________ 1 ____________________

____________________ ____________________ 0

____________________ _____________________

(3)

(b) An aluminium atom has 13 electrons. How are these arranged in shells around the nucleus?

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(c) Chromium atoms have 24 protons and 28 neutrons.

(i) How many electrons does each neutral chromium atom have?

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(ii) What is the mass number of chromium?

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(d) What change occurs to an atom which undergoes the process of reduction in a chemical reaction?

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(e) The diagram shows part of the ionic lattice of a sodium chloride crystal.

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Explain why the ions in this lattice stay in place.

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(Total 10 marks)

Q19.(a) The chart shows the reactions of the metal calcium with water, oxygen and dilute

hydrochloric acid.

Name (i) solution A _________________________________________________

(ii) solid B ___________________________________________________

(iii) gas C ____________________________________________________(3)

(b) The diagrams below show the electronic structure of an atom of calcium and an atom of oxygen.

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Describe fully what happens to its electrons when:

(i) a calcium atom forms a calcium ion. State the charge on the calcium ion formed.

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(ii) an oxygen atom forms an oxygen ion. State the charge on the oxygen ion formed.

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(c) Calcium oxide is an ionic compound. Why do ionic compounds have high melting points?

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(Total 11 marks)

Q20.Atoms of calcium, phosphorus and fluorine are represented below, each with its mass number and proton number.

(a) Use this information to complete the table.

CALCIUM PHOSPHORUS FLUORINE

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Number of protons in the nucleus 20 9

Number of neutrons in the nucleus 20 16

Number of electrons 15 9

(3)

(b) Calcium and fluorine atoms can combine to form the compound calcium fluoride, CaF2.

The fluoride ion is represented by F–.

(i) Explain how the fluorine atom forms a fluoride ion.

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(ii) How is the calcium ion represented?

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(c) Phosphorus and fluorine form a covalent compound, phosphorus trifluoride.

Complete the sentences below which are about this compound.

Phosphorus trifluoride is made up of phosphorus and fluorine ________________

These are joined together by sharing pairs of ________________________ to form

phosphorus trifluoride ____________________________ .(3)

(d) (i) Sodium chloride, an ionic compound, has a high melting point whereas paraffin wax, a molecular compound, melts easily.

Explain why.

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(ii) Molten ionic compounds conduct electricity but molecular compounds are non-conductors, even when liquid.

Explain why.

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______________________________________________________________(2)

(Total 14 marks)

Q21.Solder is an alloy of lead and tin.

The table shows how the percentage of tin affects some of the properties of solder.

Percentage(%) of tin

Tensile strength in MPa

Melting pointin °C

Densityin g per cm3

0 12 347 11.35

20 33 257 10.40

40 37 187 9.28

60 52 153 8.52

Tensile strength is the ability to support a load without breaking.

Use information from the table to answer these questions.

(a) What is the density of pure lead?

Density = _______________ g per cm3

(1)

(b) How does increasing the percentage of tin affect the properties of solder?

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(c) Solder was used when plumbers joined lead pipes together. Solder, not pure lead, was used to make the joints.

Suggest one reason why.

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(Total 5 marks)

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