AQA GCSE Physics: Combined Science

Topic Questions

4.1 Atoms & Isotopes

1a1 mark

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

1b2 marks

Table 1 describes four nuclides. The nuclide notation for lead-206 is missing.

Table 1

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  

Complete the table by filling in the nuclide notation for lead-206. State which two nuclides have the same number of protons.

1c3 marks

Using the information from Table 1, complete the following table.

 

Which two nuclides have the same number of nucleons?  
Which two nuclides have the same number of neutrons?   
Which one of the four nuclides has the most electrons orbiting when it is in a neutral atom?  
 
1d1 mark

State what must be true for an atom to have neutral overall charge.

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2a1 mark

Figure 1 shows two different models of an atom.

Figure 1

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

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.

2b3 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 ..........................................

2c2 marks

An electron is removed from the atom, as shown in Figure 2.

Figure 2

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

State the name given to this type of atom. Describe the effect of removing the electron on the overall charge of the atom.

2d3 marks

State the number of protons, neutrons and electrons in an atom of Li presubscript 3 presuperscript 7.

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3a2 marks

Rutherford used the scattering of α-particles to provide evidence for the structure of the atom.

The apparatus includes an α-particle source fired at a gold foil inside a vacuum chamber.

Which two of the following are reasons why there must be a vacuum in the chamber?

Tick (✓) two boxes.   

Gamma radiation needs to be removed square
Air molecules would cause scattering square
To prevent the α-particles being absorbed or scattered square
So that the gold foil doesn't tarnish square
3b4 marks

The equipment Rutherford used is shown in Figure 1.

Figure 1

4-1-e-3b-rutherford-scattering-equipment

Label the diagram using words or phrases from the box below. Each answer should be used once.

gold foil detector α-source vacuum chamber
3c4 marks

Figure 2 shows  particles incident on a layer of atoms in a gold foil.

Figure 2

 4-1-e-3c-alpha-particle-scattering

Match each of the numbers 1-4 with the statements below:

Statement Number
Deflected downwards  
Continues undeflected  
Deflected backwards  
Deflected upwards  

3d3 marks

Following Rutherford's experiment, Niels Bohr came up with a modified model.

Complete the sentences about Bohr's model. 

Choose answers from the box. 

Each answer should be used once.

energy levels nucleus greater

 

Electrons orbit the .................... at different distances.


The different orbit distances are called .................... .


The further away from the nucleus the .................... the energy.    

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1a2 marks

The deflection of α-particles by a thin metal foil is investigated with the arrangement shown in Figure 1.

Figure 1

4-1-h-1a-rutherford-scattering

The detector of α-particles, D, is moved around the path labelled WXY.

State the environment the apparatus must be enclosed in and explain why this is required for the experiment.

1b4 marks

Explain the readings detected by D and the conclusions that were made about the nature of atoms at points W and X.

1c2 marks

State what the readings detected by D at position Y conclude about the charge of the nucleus. Explain why.

1d4 marks

A beam of α-particles produces a current of 3.5 pA.

Calculate the number of α-particles per second passing a point in the beam.

You will need to use the equations for current.

1 pA = 10−12 A

The charge on a proton is 1.60 × 10–19 C

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2a1 mark

Figure 1 represents a neutral atom of an isotope of element X.

4-1-h-2a-neutral-atom

Figure 1

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

2b3 marks

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 nuclear notation, for:

 
hydrogen-1 ...................................
 
hydrogen-2 ...................................
 
hydrogen-3 ...................................
2c3 marks

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

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

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

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3a2 marks

Explain what is meant by the term ‘neutral atom’. 

Refer to the number of electrons and protons.

3b1 mark

N presubscript 7 presuperscript 14 is an example of nuclide notation for the element nitrogen.

Determine the number of neutrons in nitrogen.

3c2 marks

Write the nuclide notation for another possible isotope of nitrogen.

3d4 marks

Figure 1 shows the processes of excitation and ionisation.

Figure 1

4-1-h-3d-excitation-and-ionisation

Identify which of A and B is excitation and which is ionisation. Give a definition for each process.

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1a4 marks

In 1909, Rutherford, Geiger and Marsden developed an experiment where alpha particles were scattered from gold foil.

Figure 1 shows the paths of some of the alpha particles that were fired at the gold foil during the experiment.

Figure 1

fig-1-4-1-medium-aqa-gcse-physics

Explain how the paths of the alpha particles were used to develop the nuclear model of the atom.

1b3 marks

In 1913, Niels Bohr improved upon Rutherford’s nuclear model by suggesting that electrons orbited the nucleus at particular distances.

Explain how the distance at which an electron orbits the nucleus can be changed.

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2a2 marks

Two isotopes of uranium are uranium-238 and uranium-235

The nuclear symbols for these are shown below.

q2-img-1-4-1-medium-aqa-gcse-physics q2-img-2-4-1-medium-aqa-gcse-physics

What is meant by the term ‘isotope’?

2b1 mark

How many protons are in the nucleus of a U presubscript 92 presuperscript 238 atom?

2c1 mark

How many neutrons are in the nucleus of a U presubscript 92 presuperscript 238 atom?

2d1 mark

What is the mass number of a U presubscript 92 presuperscript 235 atom?

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34 marks

In the early 20th century, one model of the atom which was popular was the ‘plum pudding’ model, shown in Figure 2.

Figure 2

fig-2-4-1-medium-aqa-gcse-physics

In 1909, Rutherford, Geiger and Marsden suggested a new model of the atom, called the ‘nuclear’ model, shown in Figure 3.

Figure 3

fig-3-4-1-medium-aqa-gcse-physics

Describe the differences between the two models.

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4a1 mark

Rutherford’s experiment, as shown in Figure 4, was designed to test the plum pudding model.

It involved firing alpha particles at a thin sheet of gold foil, and then detecting which direction the alpha particles left the gold foil.

Figure 4

fig-4-4-1-medium-aqa-gcse-physics

The plum pudding model predicted that alpha particles would pass straight through the atom with very few deflections, and even those would be small: no more than 4°.

The results of the experiment were that most of the alpha particles did go straight through, but some were deflected through large angles, and around 1 in 8000 was deflected straight back at the alpha source.

Why did this model lead to the plum pudding model being replaced by the nuclear model?

4b3 marks

Figure 5 shows the paths of three of the alpha particles that were fired at the gold foil.

Figure 5

fig-5-4-1-medium-aqa-gcse-physics

Use the nuclear model to explain the three paths, A, B, and C.

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5a2 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.

5b3 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 number of protons number, the mass number and the number of neutrons in this isotope. 

5c1 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 ...................................

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