Transcript Radioactivity_answers

1. Number of radioactive emissions/counts per
second – also known as “rate of decay”
Activity
2. Release of alpha particle from
unstable nucleus (a 2+ helium ion or a
helium nucleus)
Alpha emission
3. Number of protons in a nucleus
Atomic number
4. Natural radiation from everyday surroundings
Background radiation
5. Negatively charged subatomic particle
Electron
6. Rutherford experiment where he bombarded
a thin gold foil with alpha particles in a
vacuum
Gold foil experiment
7. Time taken for half the radioactive
nuclei in a sample to decay
Half life
8. Same number of protons, different number of
neutrons or same element but different
number of neutrons
Isotope
9. Number of protons and neutrons
Mass number
10. Small, dense centre of atom containing
neutrons and protons
Nucleus
11. Ability of radioactive emissions to pass
through materials
Penetrating ability
12. Emission of α, β or γ in order to transmute
(change contents of nucleus) or to lose
excess energy
Radioactive decay
13. The way the model suggests the atom is
arranged (Dalton, Thomson, Rutherford)
Structure of the atom
14. Nucleus that will emit radiation
Unstable nuclei
15. Chamber with no particles inside it
Vacuum chamber