Topic 5 - Nuclear Fission and Nuclear Fusion Flashcards
What does the mass (nucleon) number of an atom show?
-The total number of protons and neutrons
What does the atomic (proton) number of an atom show?
-The number of protons
What is an isotope?
-Atoms with the same number of protons in their nucleus but a different number of neutrons
In an isotope, are the mass number and the atomic number the same?
- Atomic number=same
- Mass number=different
Using carbon-12 and carbon-14 as an example, explain how the radioactivity of an atom differs between different isotopes.
- Most elements have different isotopes but only 1/2 stable (carbon-12)
- Others tend to be radioactive (carbon-14)
What happens when an unstable isotope become radioactive?
-Decays into other elements & gives out radiation
Where does radioactivity come from?
-Unstable radioactive isotopes undergoing nuclear decay & spitting out high-energy particles or waves
What part of the atom does ionising radiation come from?
-Nucleus (when unstable)
What are the three types of radiation that can come from a nucleus when it decays (the ionising radiation)?
- Alpha
- Beat
- Gamma
Is there a pattern to when an unstable nuclei starts to decay?
- No, it is random
- Nothing can be done to force decay to happen
What is meant by ionisation?
-When an atom (with no overall charge) gains or loses an electron to turn it into an ion (with an overall charge)
What charge does an alpha particle have and what effect does it have on atoms?
- Strong positive charge
- When an alpha particle passes close to an atom, it pulls a negatively charged electron out of orbit (as like forces attract)
What charge does a beta particle have and what effect does it have on atoms?
- Negative charge
- Pushes an electron out of an atom’s orbit (like charges repel)
What effect does a gamma particle have on an atom?
- Transfers energy to the electron in atom’s orbit
- If electron gets enough energy, it can break free from atom
What is an alpha particle and what is it made up of?
- Helium nuclei
- Two protons and two neutrons
How ionising is an alpha particle and why?
- Strongly ionising
- Due to their big mass and charge (also makes them slow)
- Able to remove electrons from lots of atoms creating lots of ions
How penetrative is an alpha particle?
-Don’t penetrate far into material and are stopped easily
How ionising and how penetrative is a beta particle?
-Moderately ionising and moderately penetrative (quite fast and quite small being an electron)
What change goes on in the nucleus when a beta particle is emitted?
-A neutron turns into a proton
What is a beta particle?
-Electrons emitted from a nucleus
What is gamma radiation?
-Electromagnetic radiation (wave)
How ionising and how penetrative is gamma?
- Weakly ionising
- Penetrates a long way
What materials block each type of ionising radiation?
- Alpha particles are blocked by paper and cardboard
- Beta particles are blocked by thin aluminium
- Gamma rays are blocked by thick lead
What is nuclear fission?
A type of nuclear nuclear reaction that is used to release energy from uranium (or plutonium) atoms (i.e. in a nuclear reactor). Huge amounts of energy can be released in this way through a chain reaction.
