AQA GCSE SCIENCE A

CHEMISTRY UNIT 2

Workbook

THE FUNDAMENTAL IDEAS IN CHEMISTRY

ATOMS

THE PERIODIC TABLE

CHEMICAL REACTIONS

Steve Bishop

January 2013

Name: ……………………………………….. Date: ……………………………………

2

On the periodic table colour the following non-metals:

He, C, N, O, F, Ne, P, S, Cl, Ar, Se, Br, I, Rn

Are Kr and Xe metals or non-metals? Why?

Use another colour to shade in the semi-metals:

B, Si, Ge, As, Sb, Te, At.

What do you notice? Are there any patterns?

3

The atom

This is a representation of an atom.

Label the following: electron, proton, neutron and nucleus

Complete with the following terms:

Atom

Compounds

Electron

Mass number

Neutron

Periodic table

Proton

Proton no (atomic no)

Groups (down)

Molecule

No of electrons in outer shell

No of electron shells

4

Atomic structure and the Periodic table

Atomic structure 1. What are the three major component particles of atoms?

…………………………….., …………………………… and …………………………

2. How do particles compare in mass and charge?

Symbol Mass Charge

Neutron

Proton

Electron

Complete these sentences

3. The number of protons in the nucleus of an atom is known as the ……………… number,

When a neutral atom loses an electron ………………. Ion is formed, and when a neutral

atom gains an electron a …………… ion is formed.

4. Complete the table

Element Symbol Atomic

number

Mass

number

Number of

particles in the

nucleus

Number of electrons in

each shell

Protons Nucleus First

shell

Second

shell

Third

shell

Hydrogen 1 1 1 0 1

He

Li

Be

B

C

N

O

F

5. Which groups in the Periodic table contain: (a) only metals (b) only non-metals and (c)

both metals and non-metals?

5

Use the periodic table to answer the following questions:

Which group and period is Argon in? ………………. How many electron shells does Argon have? ………………. How many electrons in the outer shell? ………………. Complete the table:

Proton number

Mass number

Period

Group

Element

6

Heating substances Procedure heat one small spatula

scoop of each substance in a dry test

tube over a blue Bunsen flame.

Wear eye protection and wash hands

after use. Heat in well ventilated room.

Do not breathe in the fumes.

Heating copper carbonate

Observation (Describe the powder before heating)

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Prediction (What will happen when heated?)

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Observation (What happened when heated?)

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Explanation (Why did it happen?)

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Copper carbonate is a green powder, when heated produced a black powder and carbon

dioxide gas.

This type of reaction is called thermal decomposition.

We can write an equation for this reaction:

Copper carbonate → black powder + carbon dioxide gas

Suppose one particle of copper carbonate looks like this:

and one particle of carbon dioxide looks like this:

What does one particle of the black powder look like?

Draw it as you think it should be:

What do you think the black powder is called?

Use diagrams as those above to ‘draw’ the chemical equation for this.

Can you write down in symbols the reaction that has taken place?

8

Heating lead nitrate Observation (Describe the powder before heating)

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Prediction (What will happen when heated?)

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Observation (What happened when heated?)

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Explanation (Why did it happen?)

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YouTube clip http://www.youtube.com/watch?v=csEnz9ZsAFM

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Lead nitrate →yellow powder + gas

Suppose the yellow powder looks like this

And a particle of the gas looks like this

What do you think a particle of lead nitrate (the white powder) looks like? Draw it below:

Write an equation to show what happens to one particle of lead nitrate when it is heated.

Use the diagrams to represent the particles.

What do you think the yellow powder left in the tube is called?

10

Heating potassium permanganate

Observation (Describe the powder before heating)

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Prediction (What will happen when heated?)

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Observation (What happened when heated?)

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Explanation (Why did it happen?)

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Potassium permanganate → brown powder + oxygen

Suppose a particle of potassium permanganate looks like this:

And a particle of oxygen looks like this:

What do you think a particle of brown powder looks like?

Draw what you think it should be like:

What do you think the brown powder is called?

Use diagrams to represent the chemical equation for this reaction.

12

For lead nitrate:

Observations on heating

Colour change from white to yellow

Fumes given off – a gas is produced

Brown fumes suggest nitrogen dioxide is produced.

A glowing splint would relight – oxygen gas is produced

The chemical reaction is

2Pb(NO3)2(s) → 2PbO(s) + 4NO2(g) + O2(g)

13

Writing chemical equations Complete the table

Substance Number of atoms present in one

molecule

Formula

Water 2 hydrogen, 1 oxygen

Alumina 2 aluminium, 3 oxygen

Quartz 1 silicon, 2 oxygen

Ammonia 1 nitrogen, 3 hydrogen

Methane 1 carbon, 4 hydrogen

Calcium oxide CaO

Sugar C6H12O6

Sodium thiosulphate Na2S2O3

Ethanol C2H5OH

Calcium carbonate CaCO3

Copper nitrate Cu(NO3)2

Rules for writing a formula of a compound

• The chemical formula of a compound represents the smallest particle present • The formula shows the symbol of each atom present, a small number below the line

shows where there is more than one atom of the same kind • Where possible the symbols are written in order, so that those atoms which are

linked together are placed next to one another, In calcium sulphate (CaSO4) the O atoms are linked to the S atoms and not directly to the Ca.

• The formula of a compound containing a metal is usually written with the metal atom first: PbO not OPb

• Brackets are used to show when the same group of atoms is found more than once in the formula: Cu(NO3)2.

14

Chemical reactions Reactants Products Word equation

Hydrogen + Oxygen →

Water

Picture

Symbol

2H2 + O2

→

2H2O

Check:

do they balance?

4 H and 2 O 4 H and 2 O

Reactants Products Word equation

Ethanol + ______________

→

Carbon dioxide +

______________

Picture

Symbol

C2H6O + 3 ____ →

_______ + 3H2O

Check:

do they balance?

2 C, 6H, ______ , ______

_______, 6H, 7O

15

Reactants Products Word equation

Nitrogen + _____________

→

Ammonia

Picture

Symbol

N2 + _______ →

2________

Check:

do they balance?

2N, ______

_________, 6H

Now do the same for the following:

copper carbonate → copper oxide + carbon dioxide

lead nitrate → lead oxide + nitrogen dioxide + oxygen

magnesium + oxygen → magnesium oxide

copper + oxygen → copper oxide

Which of the above are (a) oxidations or (b) thermal decompositions?

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Elements, compounds and mixtures

Place these substances in the correct column

Oxygen

Carbon dioxide

Magnesium

Milk

Sand

Limestone

Element Compound Mixture

In the flasks are the particles of four different gases. (Each circle represents an atom.)

Which represents (a) an element …………….. and (b) a compound …………………

17

Fill in the boxes with the correct terms:

Elements Molecules Compounds

In each of the boxes draw images to represent an element, a compound and a mixture

Element Compound Mixture

Pure substances

__________

Atoms __________

__________

Molecules

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Key terms

Explain the meaning of these key terms:

Atom ……………………………………………………………………………………

……………………………………………………………………………………………

Element …………………………………………………………………………………

……………………………………………………………………………………………

Compound ………………………………………………………………………………

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Periodic table …………..………………………………………………………………

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Nucleus …………………………………………………………………………………

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Proton ……………………………………………………………………………………

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Neutron …………………………………………………………………………………

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Atomic number …………………………………………………………………………

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Mass number ..…………………………………………………………………………

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Energy level ……………………………………………………………………………

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Electron shell ..…………………………………………………………………………

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Noble gases ……………………………………………………………………………

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Unreactive ………………………………………………………………………………

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Stable …………..………………………………………………………………………

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Molecules .………………………………………………………………………………

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Ions ………………………………………………………………………………………

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Covalent bonds …………………………………………………………………………

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Reaction …………………………………………………………………………………

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Reactants ………………………………………………………………………………

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Products ………………………..………………………………………………………

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AQA Chemistry exam-style questions

Q1. Choose words from this list to complete the sentences below.

carbonate chloride compound mixture oxide solution

(a) When two elements react, the new substance formed is called a .............................. . (1)

(b) The white powder formed when zinc reacts with oxygen is called zinc .......................... . (1)

(Total 2 marks)

Q2. The diagram shows the structure of a lithium atom.

(a) (i) What is represented by .................................................................................

(ii) What is represented by ........................................................................... (2)

(b) What is the symbol for lithium? ................................................................................ (1)

(Total 3 marks)

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Q3. The diagram represents an atom. Choose words from the list to label the diagram.

electron ion neutron nucleus

(Total 3 marks)

Q4

Sando-K is a medicine. It is given to people whose bodies contain too little of a particular element.

Sando-K is a mixture of two compounds. The formulae of the two compounds are given below.

KHCO3 KCl

(a) Use the Data Sheet to help you to name all the elements in these compounds.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(b) Which metal do people given Sando-K need?

..................................................................................................................................... (1)

(Total 4 marks)

23

Q5. (a) The list below gives six substances.

• aluminium

• beer

• copper

• milk

• pure water

• sodium chloride

Put each substance in the correct column of the table.

ELEMENTS COMPOUNDS MIXTURES

(3)

(b) Elements can be divided into two groups, metals and non-metals.

The list below gives some properties of elements.

• brittle

• can be hammered into shape

• dull

• good conductors of electricity

• poor conductors of electricity

• shiny

Put each property into the correct column.

PROPERTIES OF METALS PROPERTIES OF NON-METALS

(3)

24

Q6. In the flasks are the particles of four different gases. (Each circle represents an atom.)

(a) Which diagram represents

(i) oxygen, O2 .................................. (1)

(ii) steam, H2O ................................. (1)

(b) The gases in A and B are elements and the gases in C and D are compounds. Explain why.

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.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 5 marks)

25

Q7. About 100 years ago a scientist called J. J. Thomson thought that an atom was a ball of positive charge with negative particles stuck inside. Today a different model is used. The diagram shows how an atom of carbon is represented by this model.

(a) The negative particles are called electrons.

(i) What is the name of the positive particles ?

........................................................................................................................... (1)

(ii) What particle is represented by ●?

........................................................................................................................... (1)

(iii) What is the central part of the atom called that contains both and ●?

........................................................................................................................... (1)

(b) Use the model to explain why the six electrons are arranged as shown.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 5 marks)

26

Q8. The diagram shows a light bulb.

(a) (i) An argon atom has the structure shown. Use the words in the box to label the particles in the atom. Each word should only be used once.

electron neutron proton

(2)

(ii) Argon is unreactive. Why?

.....................................................................................................................

..................................................................................................................... (1)

(b) Oxygen would not be a suitable gas to use in a light bulb. Explain why.

................................................................................................................................

................................................................................................................................ (2)

(Total 5 marks)

27

Q9. (a) The diagram represents an atom of beryllium. Use words from the box to label the diagram.

electron ion isotope molecule nucleus

(2)

(b) Use crosses (x) to complete the diagram to show the electronic structure of a magnesium atom. The atomic (proton) number of magnesium is 12.

(2)

(Total 4 marks)

28

Q10. The diagram represents the electronic structure of an atom of an element.

The periodic table on the Data Sheet may help you with this question.

(a) Name this element.

........................................................................................................................... (1)

(b) Complete this sentence.

The nucleus of an atom contains neutrons and .......................................................... (1)

(Total 2 marks)

Q11. John Dalton wrote these statements in 1808.

• “All substances are made of a vast number of extremely small particles called atoms.”

• “Every particle of water is like every other particle of water, every particle of hydrogen is like every other particle of hydrogen, etc.”

(a) “Every particle of water is like every other particle of water.” Use Dalton’s ideas and your knowledge of water to explain why.

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

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(b) Dalton thought that all atoms of an element are exactly the same. We now know that it is possible to have atoms of the same element but with different mass numbers. The diagrams represent two atoms of hydrogen.

State, in terms of particles, how these two atoms are different.

.....................................................................................................................................

..................................................................................................................................... (1)

(Total 3 marks)

Q12. Hydrogen is an element.

(a) The diagram shows the parts of a hydrogen atom.

Use words from the box to label the diagram.

electron group nucleus symbol

(2)

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(b) Hydrogen can be used as a clean fuel for cars.

(i) When hydrogen burns in air, it reacts with another element.

Complete the word equation for this reaction.

hydrogen + ................................. → water (1)

(ii) Suggest one reason why hydrogen is called a clean fuel.

.........................................................................................................................

......................................................................................................................... (1)

(Total 4 marks)

Q13. Hot air balloons burn hydrocarbons to heat the air.

(a) The hot air contains these gases: nitrogen, N2 oxygen, O2 argon, Ar carbon dioxide, CO2 water vapour, H2O

(i) Argon is an element.

What is an element?

...........................................................................................................................

........................................................................................................................... (1)

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(ii) Name one other gas in the hot air that is also an element.

........................................................................................................................... (1)

(b) Propane, C3H8, can be represented as:

H H H │ │ │

H C C C H │ │ │ H H H

Use the correct words from the box to complete the sentences.

bond carbon compound element mixture

(i) Propane is a ....................................... and is made up of atoms of hydrogen

and ....................................... (2)

(ii) Each line between the atoms in propane represents a chemical ....................... (1)

(Total 5 marks)

32

Q14. Limestone has been called the Earth’s most useful rock.

(a) Limestone contains calcium carbonate, CaCO3.

(i) Complete the table to show the number of atoms of each element in the formula of calcium carbonate.

Calcium has been done for you.

Element Number of atoms in the formula CaCO3

Calcium, Ca 1

Carbon, C

Oxygen, O

(2)

(ii) The diagram below represents a carbon atom.

Use words from the box to label the parts of this atom.

bond electron molecule nucleus

(2)

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(b) At a cement works, limestone is mixed with clay and heated in a kiln.

Use the information in the diagram to answer these questions.

(i) Name the fuel that is used to heat the limestone and clay.

........................................................................................................................... (1)

(ii) Limestone contains calcium carbonate, CaCO3.

Draw a ring around the correct gas in the box to complete the sentence.

The gas formed when calcium carbonate decomposes is

argon.

carbon dioxide.

nitrogen.

(1)

34

(c) The cement works starts to burn a different fuel.

Local residents are concerned because more children are suffering asthma attacks. Residents have also noticed that parked cars are becoming dirty because of smoke particles from the chimney.

The table shows the possible medical risk from smoke particles.

Particle size in mm Medical effect

Larger than 0.4 No medical risks known

0.3 and smaller Causes asthma attacks

0.2 and smaller May cause cancer

(i) Give two reasons why local residents are concerned about the cement works burning a different fuel.

1 ........................................................................................................................

...........................................................................................................................

2 ........................................................................................................................

........................................................................................................................... (2)

(ii) The company operating the cement works stated that smoke particles from the chimney had not changed since it started burning the different fuel.

If you were a local resident, what evidence would you like to see to help you decide if the company’s statement is true or not?

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

........................................................................................................................... (2)

(Total 10 marks)

35

Q15. A substance made of only one type of atom is called an element.

The chemical symbols and positions of six elements in the periodic table are shown.

Draw a straight line from each description to its correct symbol.

Description Symbol

Al

A metal with a low density that does not corrode easily

Fe

It has properties similar to those of sodium, Na

He

It is a transition metal

Li

It is a noble gas

O

(Total 4 marks)

36

Q16. Atoms are made up of three main particles.

(a) Complete the table to show the names and charges of the particles in an atom.

Name of particle Charge

proton

0

electron –1

(2)

Use the periodic table on the Data Sheet to help you answer these questions.

(b) Why are lithium and sodium in the Group 1 of the periodic table?

........................................................................................................................

........................................................................................................................ (1)

(c) Helium is in Group 0 of the periodic table.

(i) Give one property of helium that is the same as other gases in Group 0.

.............................................................................................................. (1)

(ii) Give one property of helium that is different from other gases in Group 0.

.............................................................................................................. (1)

(Total 5 marks)

37

Q17. A substance made of only one type of atom is called an element.

(a) The diagram represents the structure of an atom.

(i) What does the diagram tell you about this atom?

..............................................................................................................

..............................................................................................................

..............................................................................................................

..............................................................................................................

..............................................................................................................

.............................................................................................................. (3)

(ii) The atom of a different element has an atomic number of 5 and a mass of 11. How many neutrons are in this atom?

..................................... (1)

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(b) The chemical symbols and positions of six elements in the periodic table are shown.

Draw a straight line from each description to its correct symbol.

Description Symbol

Al

A metal with a low density that does not corrode easily

Fe

It has properties similar to those of sodium, Na

He

It is a transition metal

Li

It is a noble gas

O

(4) (Total 8 marks)

39

Q18. (a) The chemical equation for a reaction of sodium is shown below.

2Na + Cl2 → 2NaCl

Describe this reaction of sodium in terms of the names of the substances and the numbers of the atoms involved.

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................ (3)

(b) Use the periodic table on the data sheet to help you to answer this question.

(i) Complete the electronic structure of sodium.

(2)

(ii) How is the electronic structure of sodium different from the electronic structure of chlorine?

...............................................................................................................

............................................................................................................... (1)

(Total 6 marks)

40

Q19. There are millions of different substances that make up our world. All these substances are made from chemical elements.

(a) What is an element?

.....................................................................................................................................

..................................................................................................................................... (1)

(b) Many substances are compounds. What is a compound?

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 3 marks)

Q21. Carbon is an important element in maintaining life.

(a) Draw and label a diagram of an atom of carbon. Include the correct names of the particles.

(4)

(b) Use your diagram to give the atomic number and mass number of carbon.

Atomic number ............................................................................................

Mass number ............................................................................................... (2)

41

Q23. Lithium has an electronic configuration of 2, 1. Fluorine has an electronic configuration of 2, 7.

Describe how both lithium and fluorine form ions to make lithium fluoride.

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............................................................................................................................... (Total 4 marks)