Radioactivity Flashcards
Definition of isotopes
Isotopes have the same number of protons but different numbers of neutrons in the nucleus
Why are isotopes less stable than the original structure?
Isotopes are less unstable than the original structure due to the fact that they have more neutrons than protons hence, they do not have a balance of protons and neutrons
What is meant by the stability of atomic nuclei?
Stability, in the context of the atomic nuclei, pertains to the balance of the strong nuclear forces
What can cause a nucleus to be stable or unstable
With the correct balance of protons and neutrons, a nucleus is stable - too many or too few neutrons causes it to be unstable
Describe the process of radioactive decay
Radioactive decay of an unstable nucleus is random and it is not affected by temperature and pressure. As it decays, it emits a particle in order to make it more stable and balance the internal nuclear forces.
What does the term ionising mean
Ionising is when radioactive particles can ionise atoms they collide with and it alters the structure of the atom by knocking off valence electrons hence, leaving behind ions.
Describe properties of Alpha Particles
Alpha particles are
- Highly ionising as it has more of a chance to knock off a particle due to its mass
- Weakly penetrating and can be stopped by a sheet of paper or a few cm in air
- Deflected by electric and strong magnetic fields towards negative plates
- Contains 2 protons and 2 neutrons
- The same as Helium however they have a 2+ charge
Describe the properties of Beta particles
Beta particles are:
- Moderately ionising because the particle has a smaller size
- Moderately penetrating and can be stopped by 3mm of aluminium or a few metres in air
- Deflected by electric and magnetic fields towards the positive plates
- Beta particles are fast-moving electrons
Describe the properties of Gamma rays
Gamma rays are:
- Lowly ionising as it has no mass and it’s absorbed by the atom meaning it doesn’t knock off particles
- Not particles as it is a ray hence, it has no charge
- Highly penetrating and can be stopped by centimetres of lead
- Not affected by electric or magnetic fields therefore it goes straight
Describe what neutron radiation is
Neutron Radiations are:
- non-ionising
- stopped by materials like water and concrete
In neutron-rich nuclides, one or more neutrons are ejected and are emitted during nuclear fission
What is the process of neutron radiation
- Neutrons can be emitted from an unstable nucleus to make the nucleus more stable
- Neutron radiation can be stopped by materials like water and concrete
- Neutron radiation is non-ionising though, it can cause other atoms to be radioactive
- This means the nucleus can absorb particles hence, it becomes unstable and radiation occurs
- Therefore, this makes it dangerous
How can neutrons cause other atoms to be radioactive?
Neutrons can be absorbed by other atoms and cause them to become radioactive hence, these new radioactive atoms, then, decay by emitting ionising radiation. Neutrons don’t directly cause ionisation. Neutrons are the only type of radiation to cause other atoms to become radioactive
What is meant by background radiation
Radiation that is always present due to natural sources such as rocks emitting the radiation
Are there consequences following being exposed to background radiation with a higher count rate?
Being exposed to a high dosage of radiation for long periods of time can be harmful as it can lead to increased chances of cancer
What is a chain reaction? (Nuclear fission)
process in which neutrons released in nuclear fission produce additional nuclear fission in at least one further nucleus.
