Atomic structure

Question 1

What are the types of radiation

Answer 1

Alpha (α) - 2 protons and neutrons
Beta (β) - fast moving electrons
Gamma (γ) - electromagnetic waves
Neutron (n) - neutron

Question 2

What are the properties of radiation

Answer 2

Alpha:
Stopped by paper
Travel a few centimetres
Very strong ionising power

Beta:
Stopped by aluminium
Travel a few metres
Medium ionising power

Gamma:
Stopped by thick lead
Travel a great distance
Weak ionising power

Question 3

How much do alpha, beta and neutron decay

Answer 3

4 He
2

0 e
-1

1 n
0

Question 4

What is half life

Answer 4

The time it takes for half the nuclei in a radioactive sample to decay

Question 5

What is the difference between contamination and irradiation

Answer 5

Contamination - the radioactive source is on or in the object/body (increase risk from gamma)
Irradiation - an object or body is exposed to nuclear radiation (increase risk from alpha)

Question 6

What are the advantages and disadvantages of contamination

Answer 6

Advantages:
Use of isotopes with a short half-life means exposure can be limited
Imaging processes can replace some invasive surgical procedures

Disadvantages:
Exposure to radioactive materials can potentially damage healthy cells
It can be difficult to ensure that the contamination is fully removed so small amounts of radioisotope may still be left behind

Question 7

What are the advantages and disadvantages of irradiation

Answer 7

Advantage:
Sterilisation can be done without high temperatures
It can be used to kill bacteria on things that would melt

Disadvantages:
It may not kill all bacteria on an object
It can be very harmful