Topic 11 Flashcards
What two processes can cause electrons to change energy levels
- Large heat increase
- The presence of an electrical field
What are the four scenarios in which an atom may become unstable
- The atom having too many neutrons
- The atom having too few neutrons
- The atom having too much mass
- The atom having too much energy
How do unstable nuclei become more stable
Unstable nuclei are radioactive, so emit radiation in order to become more stable.
They type of radiation they emit depends on what makes them unstable
What are the constituents of an alpha particle
Two protons and two neutrons
What are penetration capabilities of alpha radiation
Alpha particles are weakly penetrating and so are stopped by a few centimetres of air or a sheet of paper
What does beta-minus radiation consist of
High-energy electrons
What does beta-plus radiation consist of
High-energy positrons
What are the penetration capabilities of beta-minus radiation
Beta-minus radiation has medium penetrative capabilities and is stopped by a few mm of aluminium or around 1 m of air
What are the penetration capabilities of beta-plus radiation
Beta-plus radiation is almost instantaneously annihilated by electrons and so has virtually zero range
What is gamma radiation
Gamma radiation is a form of high-energy electromagnetic radiation
What charge do gamma rays have
Gamma rays are a form of electromagnetic radiation and so don’t have a charge
Which type of radiation is most ionising
Alpha radiation
Which type of radiation is most weakly ionsing
Gamma radiation
What type of radiation travels the fastest and at what speed
Gamma radiation travels the fastest since it is a type of electromagnetic radiation and so travels at the speed of light
Under what circumstance is alpha radiation emitted
When a nucleus has too much mass