Atomic Structure (Edexcel GCSE Physics)

(i) Use words from the box to complete the sentences below about ions. 

Atoms may form positive ions by ........................ electrons.  The electrons involved in forming positive ions are the ...................... electrons.

[2]

(ii) Which of these radiations is both electromagnetic and ionising? 

☐ A alpha

☐ B beta minus

☐ C gamma

☐ D neutron 

[1]

(iii) Which type of radiation will travel the shortest distance in air?  

☐ A alpha

☐ B beta minus

☐ C beta plus

☐ D gamma

[1]

Lead-214 is a radioactive isotope.

(i) State one way in which radioactive isotopes can be harmful to people. 

[1]

(ii) Lead-214 emits - particles.

Describe what happens to the nucleus of a lead-214 atom when it emits a - particle.

[2]

The typical size of an atom is

The mass of a proton is 1.6726 x 10^-27 kg.

The mass of an electron is 9.1094 x 10^-31 kg.

Calculate how many times the mass of a proton is greater than the mass of an electron.

Give your answer to two significant figures. 

................................... times

Carbon-13 and carbon-14 are isotopes of carbon. Nuclei of carbon-13 and carbon-14 can be represented by these symbols  

and 

Complete the table for an atom of carbon-13 and an atom of carbon-14.

(i) State the name of an instrument that can be used to measure radioactivity. 

[1]

(ii) State two sources of background radiation.

[2]

Carbon-14 is radioactive and has a half-life of 5 700 years.

The number of radioactive carbon-14 atoms in a very old piece of wood is found to have decreased from 1 000 000 to 125 000.

Determine the age of the piece of wood.

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

Carbon-14 decays into nitrogen-14.

The symbol for nitrogen-14 is

Explain what happens in a carbon-14 nucleus when it decays to a nitrogen-14 nucleus.

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

Refer to the number of electrons and protons.

An example of nuclide notation for the element nitrogen is .

Determine the number of neutrons in . 

Write the nuclide notation for another possible isotope of nitrogen.

Figure 1 shows the process of excitation.

Figure 1

Explain the process of excitation.

An experiment conducted by Rutherford, Geiger and Marsden provided evidence for the structure of the atom.

Alpha particles were fired at a thin gold foil, with a detector to detect deflected particles.

The circles shown in Figure 1 represent three gold nuclei. Three α-particles are approaching the gold nuclei.

Figure 1

Complete the paths of the α-particles.

Suggest why: 

(i) The majority of alpha particles went straight through the gold foil.

[1]

(ii) Some alpha particles deflected through small angles.

[1]

(iii) Only a small number of alpha particles deflected straight back at angles of  greater than 90°

[1]

A neutral carbon-14 atom can be written symbolically as:

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]

Carbon-12 is another isotope of carbon.

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

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

Figure 1 

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.

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

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

Explain why. 

A beam of α-particles produces a current of 4.2 pA.

1 pA = 10⁻¹² A

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

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

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

Figure 1

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

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 .

Write down the symbols, using nuclear notation, for:  

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

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

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

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 nuclear notation, the equation that represents this reaction.

A student is designing revision material on atomic structure. 

They design the table shown in Figure 1 below, with the properties of the particles that make up an atom:   

Figure 1 

Some of the information in Figure 1 is missing.

Complete the missing information.

The student wonders how to come up with an explanation for the term ‘neutral atom’.

By referring to the number of electrons and protons, explain what is meant by the term ‘neutral atom’. 

To show an example of isotope notation, the student inserts an image of the element nitrogen into their revision notes, as shown in Figure 2 below.

Figure 2

Use Figure 2 to determine the number of neutrons in nitrogen.

The student wishes to design a section on isotopes in the revision material.

They draw another image, as shown in Figure 3:

Figure 3

Use Figure 3 to show a possible isotope of nitrogen, filling in the missing spaces.