Radioactivity

Question 1

Neutron

Answer 1

Found in the nucleus, 1 mass, no charge

Question 2

Proton

Answer 2

Found in the nucleus, 1 mass, positive charge

Question 3

Electron

Answer 3

Found in the shell, negligible mass, negative charge

Question 4

Atomic number

Answer 4

The number of protons in an atom

Question 5

Mass number

Answer 5

The total number of protons and neutrons in the nucleus of an atom

Question 6

Isotope

Answer 6

Different atoms of the same element, with the same number of protons but a different number of neutrons. Also have the same chemical properties

Question 7

What are alpha and betas particles and gamma rays?

Answer 7

Ionising radiations emitted from unstable nuclei in a random process

Question 8

Alpha (Composition, Charge, Mass, Speed, Penetrability, Ionisation, Stopped by, Deflected by)

Answer 8

• 2 protons + 2 neutrons
• +2
• 4
• Slow
• Low penetrating power
• High ionising radiation
• Stopped by paper
• Charged so it’s deflected by a magnetic field

Question 9

Beta (Composition, Charge, Mass, Speed, Penetrability, Ionisation, Stopped by, Deflected by)

Answer 9

• The same as an electron
• -1
• 1/2000 of a proton
• Fast
• Medium penetrating power
• Moderate ionising radiation
• Stopped by aluminium
• Charged so it’s deflected by a magnetic field

Question 10

Gamma (Composition, Charge, Mass, Speed, Penetrability, Ionisation, Stopped by, Deflected by)

Answer 10

• An EM wave
• No charge
• No mass
• Speed of light
• High penetrating power
• Very low ionising radiation
• Stopped by lead/concrete
• Not deflected by a magnetic field

Question 11

What can detect ionising radiation?

Answer 11

Photographic film or a Geiger-Muller detector

Question 12

What is background radiation?

Answer 12

Naturally occurring radiation around us

Question 13

What are some sources of background radiation?

Answer 13

Rocks/soil, food, cosmic rays, medical treatments and more

Question 14

What happens to the activity of a sample over time?

Answer 14

It decreases

Question 15

How is the activity of a sample measured?

Answer 15

In Becquerels

Question 16

Half-life

Answer 16

The length of time it takes for the activity of an amount of radioactive substance to half

Question 17

Uses of radioactivity

Answer 17

Medical tracers
- Half-life of 3-8 hours depending upon use
- β or γ emitters
Tracers for pipes
- Half-life of 3-8 days
- γ emitters
- Used to detect breaks along blockages

Question 18

Features of irradiation

Answer 18

• Occurs when an object is exposed to an outside source
• Doesn’t cause the object to become radioactive
• Can be blocked by adequate shielding
• Stops as soon as the source is removed
• Used for sterilising food and medical equipment and gamma cancer treatments

Question 19

Features of contamination

Answer 19

• Occurs if the source is on or in the object
• Object will be radioactive for as long as the source is in it
• The radiation cannot be blocked from the object
• It can be very difficult to remove all of the contamination
• Used for tracers

Question 20

What can ionising radiation cause?

Answer 20

Cell and DNA mutations

Question 21

Protection from radiation

Answer 21

Protective clothing
- Radiation suits
- Lead aprons
- Masks and glasses
Limit exposure time
- Radiation badges to measure
- Leaving the room for medical reasons
Handle sources with care
- Stored in a lead-lined box
- Handle with tongs

Question 22

Why is long-term storage a major problem with nuclear materials?

Answer 22

Some materials have extremely long half-lives so they remain active for thousands of years. Nuclear waste must be stored in sealed containers that must be capable of storing the radioactivity. It is stored deep underground in lead-lined containers far away from civilisation