P6 Specification

Module P6: Radioactive Materials

P6.1 Why are some materials radioactive?

1. recall that some elements emit ionising radiation all the time and are called radioactive

2. understand that radioactive elements are naturally found in the environment, contributing to

background radiation

3. understand that an atom has a nucleus, made of protons and neutrons, which is surrounded

by electrons

4. understand that the results of the Rutherford-Geiger-Marsden alpha particle scattering

experiment provided evidence that a gold atom contains a small, massive, positive region

(the nucleus)

5. understand that protons and neutrons are held together in the nucleus by a strong

force which balances the repulsive electrostatic force between the protons

6. understand that, if brought close enough together, hydrogen nuclei can fuse into helium

nuclei releasing energy, and that this is called nuclear fusion

7. understand that Einstein’s equation E = mc2 is used to calculate the energy released

during nuclear fusion and fission (where E is the energy produced, m is the mass lost

and c is the speed of light in a vacuum)

energy =              mass      ×             [speed]2

(joules, J) (kilograms, kg) ([metres per second]2, [m/s]2)

8. understand that every atom of any element has the same number of protons but the

number of neutrons may differ, and that forms of the same element with different

numbers of neutrons are called isotopes

9. understand that the behaviour of radioactive materials cannot be changed by chemical or

physical processes

10. recall that three types of ionising radiation (alpha, beta and gamma) are emitted by

radioactive materials and that alpha particles consist of two protons and two neutrons,

and that beta particles are identical to electrons

11. recall the penetration properties of each type of radiation

12. describe radioactive materials in terms of the instability of the nucleus, radiation

emitted and the element left behind

13. complete nuclear equations for alpha and beta decay

14. understand that, over time, the activity of radioactive sources decreases

15. understand the meaning of the term half-life

16. understand that radioactive elements have a wide range of half-life values

17. carry out simple calculations involving half-life.

P6.2 How can radioactive materials be used and handled safely, including wastes?

1. understand that ionising radiation can damage living cells and these may be killed or may

become cancerous

2. understand that ionising radiation is able to break molecules into bits (called ions), which

can then take part in other chemical reactions

3. recall and explain how ionising radiation can be used:

a. to treat cancer

b. to sterilise surgical instruments

c. to sterilise food

d. as a tracer in the body

4. recall that radiation dose (in sieverts) (based on both amount and type of radiation) is a

measure of the possible harm done to your body

5. interpret given data on risk related to radiation dose

6. understand that radioactive materials expose people to risk by irradiation and contamination

7. understand that we are irradiated and contaminated by radioactive materials all the time and

recall the main sources of this background radiation

8. relate ideas about half-life and background radiation to the time taken for a radioactive

source to become safe

9. recall categories of people who are regularly exposed to risk of radiation and that their

exposure is carefully monitored, including radiographers and workers in nuclear power

stations

10. understand that a nuclear fuel is one in which energy is released by changes in the nucleus

11. know that in nuclear fission, a neutron splits a large and unstable nucleus (limited to

uranium and plutonium) into two smaller parts, roughly equal in size, releasing more

neutrons

12. recall that the amount of energy released during nuclear fission is much greater than that

released in a chemical reaction involving a similar mass of material

13. understand how the nuclear fission process in nuclear power stations is controlled,

and use the terms chain reaction, fuel rod, control rod and coolant

14. understand that nuclear power stations produce radioactive waste

15. understand that nuclear wastes are categorised as high level, intermediate level and low

level, and relate this to disposal methods.

© OCR 2011 GCSE Science A