Chapter 3: Radioactivity

Question 1

Define radioactivity

Answer 1

Radioactivity is the spontaneous breaking up of certain unstable nuclei, accompanied by the emission of radiation

Question 2

Marie and Pierre Curie discovered…

Answer 2

Radium and polonium (from pitchblende ore)

Question 3

Becquerel

Answer 3

Discovered uranium compound emitted radiation

Question 4

Alpha emitter example

Answer 4

Americium-241 (smoke alarms)

Question 5

3 properties of alpha particles

Answer 5

-positive charge
-poor penetrating ability (paper)
-damaging to human cells

Question 6

3 properties of beta particles

Answer 6

-negative charge
-moderate penetrating ability (5mm aluminium)
-damaging to human cells

Question 7

3 properties of gamma rays

Answer 7

-no charge
-very high penetrating ability (thick lead)
-damaging to human cells

Question 8

Example of beta emitter

Answer 8

Carbon 14 (carbon dating)

Question 9

Example of gamma emitter

Answer 9

Cobalt-60 (cancer treatment)

Question 10

Define radioisotope

Answer 10

Radioisotopes are unstable, radioactive isotopes

Question 11

Define half life

Answer 11

The half-life of a radioactive isotope is the time taken for half of the atoms in a sample of the isotope to decay

Question 12

Main source of background radiation

Answer 12

Radon gas (formed from the decay of radioisotopes found in rocks in the ground)