The Nuclear Model of the Atom (Cambridge (CIE) IGCSE Physics)

Exam Questions

2 hours30 questions
1a2 marks

Fig. 12.1 shows a diagram to represent a helium atom, and an incomplete key.

 

f~nACQwG_q12a

Complete the key in Fig. 12.1. State the name of each particle.

1b2 marks

The table in Fig. 12.2 compares two isotopes of helium.

He presubscript 2 presuperscript 3

He presubscript 2 presuperscript 5

number of protons

number of neutrons

Fig 12.2

For each isotope, write the number of protons and the number of neutrons in the correct places in the table.

1c3 marks

The nucleus of the helium atom in (a) is the same as an α-particle.

 (i) Describe the penetrating ability of α-particles.

[1]

 

(ii) Explain why it is dangerous to swallow a source that emits α-particles.

[2]

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2a3 marks

Carbon-14 is a radioactive isotope of carbon. An atom of carbon-14 has 6 protons in its nucleus.

Another isotope of carbon is carbon-12.

 

(i) Determine the number of protons in a carbon-12 nucleus.

[1]

(ii) Determine the number of neutrons in a carbon-14 nucleus.

[1]

(iii) Determine the number of electrons orbiting the nucleus of a single carbon-14 atom.

[1]

2b1 mark

Carbon-14 decays by emitting a β-particle.

State what happens to a nucleus of carbon-14 when it emits a β-particle.

2c2 marks

People working with radioactive sources need to take safety precautions.

 (i) A shielding material can absorb ionising radiation and reduce the damage to living tissue.

 State a suitable material that will absorb all types of naturally occurring nuclear radiation.

[1]

 (ii) Apart from using shielding, state how a person can reduce the amount of ionising radiation they absorb when they handle samples of radioactive substances.

[1]

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3a1 mark

State the term used to describe nuclides which have the same number of protons but different numbers of neutrons.

3b2 marks

Table 1.1 describes four nuclides. The nuclide notation for lead-206 is missing.

name of nuclide

radium-222

radon-222

lead-216

lead-206

nuclide notation

Ra presubscript 88 presuperscript 222

Rn presubscript 86 presuperscript 222

Pb presubscript 82 presuperscript 216

 

Table 1.1

(i) State which two nuclides have the same number of protons.

[1]

 

(ii) Complete the table by filling in the nuclide notation for lead-206.

[1]

3c3 marks

Using the information from Table 1.1

(i) State which two nuclides have the same number of nucleons.

[1]

 

(ii) State which two nuclides have the same number of neutrons. 

[1]

 

(iii) State which one of the four nuclides has the most electrons orbiting when it is in a neutral atom.

[1]

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4a1 mark

Fig 1.1 show two different models of an atom.

5-1-4a-e-models-of-atoms-sq-igcse

Fig 1.1

The particles labelled X in the plum pudding model are also included in the model of the atom used today.

State the name of the particles labelled X.

4b3 marks

Use words from the box to complete the sentences about the particles in an atom in today's model. Words can be used once, more than once or not at all.

 

an electron                a neutron                a proton

 

The particle with a positive charge is ..........................................

The particle with the smallest mass is ..........................................

The particle with no charge is ..........................................

4c2 marks

An electron is removed from the atom, as shown in Fig. 1.2.

5-1-4c-e-ion-atomic-structure-sq-igcse

Fig. 1.2

(i) State the name given to this type of atom.

[1]

 

(ii) State the effect on the charge of the overall atom.

[1]

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5a3 marks

Extended tier only

Fig. 1.1 shows the names of three different processes that take place in different locations.

kNm_CrVo_nuclear-processes

Fig 1.1

Draw one line from each process to the location it takes place.

5b2 marks

Extended tier only

This passage is about the differences between nuclear fission and fusion.

Tick the correct statements in the table below

Fission is the splitting of a large nucleus into daughter nuclei

Electrons are released alongside the daughter nuclei in fission

Fusion is the joining of two nuclei into a heavier nucleus

Fission releases energy, but fusion does not

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1a3 marks

Extended tier only

A nucleus of americium-241 has the nuclide notation shown.

  space presubscript 95 presuperscript 241 A m

(i) Determine the number of neutrons in a nucleus of americium-241.

number of neutrons = ........................................................ [1]

 

(ii) Determine the charge on a nucleus of americium-241.

 

charge = ........................................................ [2]

1b2 marks

Americium-241 decays by emitting α-particles.

Put a tick in the box next to each correct statement.

 

square  α-particles are electromagnetic waves.

  square  α-particles are fast-moving electrons.

  square  α-particles are helium nuclei.

  square  α-particles are stopped by a sheet of paper.

  square  α-particles can pass through 3 cm of aluminium.

1c2 marks

Americium-241 has a half-life of 432 years. A sample contains 16 mg of americium-241.

Calculate the time it takes until only 4.0 mg of americium-241 are left in the sample.

 

time = .............................................. years 

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2a3 marks

This notation represents the nucleus of a neutral atom of carbon-14.

 straight C presubscript 6 presuperscript 14

State the number of:

 

(i) protons in the nucleus of an atom of carbon-14

[1]

(ii) electrons orbiting the nucleus of an atom of carbon-14

[1]

(iii) neutrons in the nucleus of an atom of carbon-14.

[1]

2b3 marks

Carbon-14 is an isotope of carbon. Carbon-12 is another isotope of carbon.

  Compare the nucleus of carbon-14 with the nucleus of carbon-12.

   State the similarities and differences.

2c3 marks

Scientists use carbon-14 to estimate the age of wood that is very old.

 A very old sample of wood contains 1.0 × 108 carbon-14 atoms.

 When the sample was new, it contained 8.0 × 108 carbon-14 atoms. The half-life of carbon-14 is 5700 years.

 Estimate the age of the sample of wood.

 

age of wood = ........................... years 

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3a3 marks

Use words from the box to complete the sentences about the charges in an atom. Words can be used once, more than once or not at all. 

       negative  

neutral

positive

 

The charge on the nucleus of an atom is ..........................................

  The charge on a proton is .......................................... 

   The charge on electrons orbiting the nucleus is ..........................................

3b3 marks

A nucleus of radium-226 has the nuclide notation shown.

space presubscript 88 presuperscript 226 R a

(i) Determine the number of protons in a nucleus of radium-226.

[1]

  

(ii) Determine the number of neutrons in a nucleus of radium-226.

[1]

   

(iii) Radium has another isotope, radium-223. 

     Write the nuclide notation for radium-223.

[1]

3c2 marks

Radium-226 has a half-life of 1600 years.

  A sample contains 8.0 mg of radium-226.

  Calculate the time for the sample to decay until only 1.0 mg of radium-226 remains.

 

   time = ............................................... years 

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4a2 marks

A nuclear power station uses uranium to generate thermal energy.

The fuel for the power station is an isotope of uranium.

Explain the meaning of the term isotope.

4b2 marks

When the nucleus of one particular isotope of uranium decays, it releases a β-particle. In the periodic table the entry for this isotope looks like this:

U presubscript 92 presuperscript 239

 State the proton number, the mass number and the neutron number of this isotope.

4c2 marks

A sample of rock includes some uranium-239.

The half-life of uranium-239 is 23 minutes.

Determine the fraction of the uranium-239 that remains after 46 minutes.

 

fraction remaining = ...........................................................

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53 marks

Extended tier only

The circles shown in Fig. 11.1 represent three gold nuclei. Three α-particles are approaching the gold nuclei.

screenshot-2022-11-02-at-16-31-52

On Fig. 11.1, complete the path of each α-particle.

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1a4 marks

Extended tier only

Table 1.1 shows data about nine elements.

Table 1.1

proton number

element

symbol

2

helium

He

3

lithium

Li

4

beryllium

Be

5

boron

B

6

carbon

C

7

nitrogen

N

8

oxygen

O

9

fluorine

F

10

neon

Ne

 Carbon-14 is a radioactive isotope with a nucleon number of 14. It decays by emitting β-particles.

Use data from Table 1.1 to write down the nuclide equation for this decay.

1b3 marks

A radioactive sample is placed close to a detector. The radioactive isotope in the sample has a long half-life. The detector records a count rate of 597 counts/s. Fig. 11.2 shows the readings when different materials are placed between the radioactive sample and the detector.

Material

fraction numerator c o u n t space r a t e over denominator c o u n t s divided by s end fraction

a sheet of paper 

602

a piece of thin aluminium

598

a piece of thin lead

510

 Fig. 11.2

 Explain whether any α-particles, β-particles or γ-rays are emitted by the radioactive sample.

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2a1 mark

Fig. 10.1 represents a neutral atom of an isotope of element X.

q10

State one similarity between this atom and a neutral atom of a different isotope of element X.

2b6 marks

The isotope of element X is radioactive. It decays to form an isotope of element Y by emitting a β-particle.

 (i) Using Fig. 10.1 deduce the nuclide notation for the isotope of Y produced by this decay.

nuclide notation: Y presubscript..... end presubscript presuperscript..... end presuperscript [3]

(ii) β-particles ionise the air they pass through less strongly than the same number of α-particles.

Suggest why this is so.

[3]

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3a2 marks

Extended tier only

When uranium-235 (space presubscript 92 presuperscript 235 straight U) is bombarded with a neutron, it forms an isotope of caesium (Cs) and an isotope of rubidium (Rb). 

Complete the nuclide notation for this reaction.

 

straight U presubscript 92 presuperscript 235 space plus space straight n presubscript square presuperscript square space rightwards arrow Cs presubscript square presuperscript 144 space plus space Rb presubscript 37 presuperscript square space plus space 2 straight n presubscript square presuperscript square

3b3 marks

Extended tier only

State and explain the process shown by the equation in (a)

3c3 marks

Extended tier only

(i) Describe and give a reason for the difference between the mass of the products and the reactants in the reaction from part (a)

[2]

 

(ii) State the energy transfer that takes place in the products of the reaction from part (a).

[1]

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4a1 mark

There are three naturally occurring isotopes of hydrogen: hydrogen-1, hydrogen-2 and hydrogen-3.

Hydrogen-1 is the simplest nuclide containing only one proton. Each isotope of hydrogen is represented by the symbol H.

Write down the symbols, using nuclide notation, for:

hydrogen-1 ...................................

hydrogen-2 ...................................

hydrogen-3 ...................................

4b5 marks

Extended tier only

In a fusion reactor, a nucleus of hydrogen-2 and a nucleus of hydrogen-3 undergo fusion.

 

(i) State what is meant by nuclear fusion.

[2] 

(ii) The fusion reaction produces a free neutron and one other particle.

Write down, using nuclide notation, the equation that represents this reaction.

[3]

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5a4 marks

Extended tier only

Fig 1.1 shows a neutron colliding with a nucleus of uranium-235, producing a number of products.

5-1-5a-h-uranium-235-fission-chain-reaction-sq-igcse

(i) Name the process shown in the diagram.

[1]

(ii) Complete, using nuclide notation, the equation that represents the reaction shown in Fig 1.1.

 

fission-reaction

[3]

5b3 marks

Extended tier only

Explain how the process shown in Fig 1.1 can lead to a chain reaction.

5c2 marks

Extended tier only

This process releases energy.

Explain the energy transfer taking place in this reaction.

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