Radioactivity - Ch8 Flashcards
1
Q
People who discovered radioactivity?
A
Becquerel, Curie, Curie
2
Q
Radioactivity
A
Spontaneous breaking up of unstable nuclei with the emission of one or more types of radiation.
3
Q
Half-life
A
Time taken for half of the nuclei in any given sample to decay.
4
Q
Alpha radiation
A
- 2p + 2n
- Positive
- Hellium nuclei
- Least penetrating
- Stopped by sheet of paper
- Am241 (smoke detectors)
5
Q
Beta radiation
A
- Fast moving electrons
- Negative charge
- Neutron changes to proton and electron is emitted
- More penetrating than alpha, less penetrating than gamma
- Stopped by 5mm Al sheet
- C14 (Carbon dating, archaeology)
6
Q
Gamma radiation
A
- No charge
- High energy
- Electromagnetic radiation
- More penetrating than beta and alpha
- Stopped by thick slab of lead
- Co60 (Cáncer radiation)
7
Q
Nuclear and chemical reactions
A
Nuclear:
- Release nuclear radiation
- New elements are formed
- Involves nucleus
Chemical:
- No radiation released
- No new elements are formed
- Involves electrons
8
Q
Radioisotope:
A
Radioactive isotope
9
Q
Isotope
A
Atoms of same element with same atomic number but different mass number
10
Q
Uses of radiation:
A
- Alpha: Carbon-14 carbon dating
- Beta: Americium-241 smoke detectors
- Gamma: Cobalt-60 cancer treatment
11
Q
Naturally occurring radioactive gas
A
Radon gas
12
Q
Carbon dating
A
In living things the ratio of Carbon-12 to Carbon-14 is constant
