Radioactivity

Question 1

Radioactivity

Answer 1

the spontaneous breakdown of the unstable nucleus of an atom with the emission of one or more types of radioactive radiation

Question 2

Henri Becquerel

Answer 2

Discovered radioactivity

Question 3

Marie and Pierre Curie

Answer 3

discovered polonium and radium

Question 4

Nuclear reaction

Answer 4

process which changes the structure, composition, or energy of an atomic nucleus

Question 5

Alpha particle

Answer 5

helium nucleus
- 2+ charge
- low penetrating power (can be stopped by a sheet of paper)
- high ionizing ability
- Used in smoke detector (americium-241)

Question 6

Beta particle

Answer 6

electron with a negative charge and a greater penetrating power than an alpha particle
- can be stopped by a few mm tinfoil
- used in radiocarbon dating (carbon-14)
- a neutron turns into a proton and an electron

Question 7

Gamma rays

Answer 7

high energy electromagnetic radiation. not particles. usually released with alpha or beta particles.
- used to treat cancer (cobalt-60)

Question 8

Half-life

Answer 8

time taken for half the samples in a given sample to decay

Question 9

Radioisotope

Answer 9

isotope of an element which emits radiation,
e.g. carbon-14 which emits beta particles