Chapter 4: Particles in the nucleus Flashcards
4A:
Define a nucleon
A particle that is found in the nuclei of an atom is labeled as a “nucleon.”
4A:
Define a quark
A particle of which all nucleons are composed of.
4A:
Define the “strong nuclear force.”
The strong nuclear force is a fundamental force that holds quarks together within nucleons and yields a bind between the nucleons in a nuclei.
4A:
Define the “electrostatic force,” as it relates to the nucleus.
The electrostatic force within the nucleus creates a repulsion between the protons in a nucleus.
4A:
Explain when a nucleus will be stable
If the nucleus has an atomic number below 20 then there must be an equal number of protons to neutrons for nuclear stability to be allowed.
However, if a nucleus has an atomic number between 20 and 83 then there must be a greater number of neutrons (than protons) in the nucleus for the strong nuclear force to counteract the electrostatic force repelling protons in the nucleus for it to be stable.
4A:
List some reasons for nuclear instability
1: Too many protons in the nucleus. This means the electrostatic force-repelling protons will counteract the strong nuclear force attracting nucleons within the nucleus.
2: Too many neutrons per proton in the nucleus. As neutrons need to exist in higher states of energy.
3: The atomic number of the nucleus is greater than 83, making the nuclei inherently unstable.
4A:
Define the “weak nuclear force.”
The weak nuclear force is responsible for beta decay in a nucleus as it changes the properties of quarks.
4B:
Define the term “half life.”
The half-life is defined as the time taken for half a radioactive sample to decay.
4B:
Define “radioactive decay.”
The process of an unstable isotope becoming stable through losing energy and emitting either a particle or photons.
4B:
Define “activity.”
Activity is defined as the rate at which a radioactive sample is decaying per unit of time. So, how many radioactive decays are occurring per a specified unit of time?
4C:
Define the “parent nuclei.”
The parent nucleus is the initial nucleus (which is unstable) before the occurrence of any radioactive decay.
4C:
Define the “daughter nucleus.”
The daughter nucleus is the new nuclei formed after the initial nucleus has decayed, which is more stable than the parent nuclei, but not guaranteed to be wholly stable itself.
4C:
Define “alpha decay.”
Alpha decay is the process of an unstable nucleus decaying into a more stable nucleus via the emission of an alpha particle.
4C:
Define an “alpha particle.”
An alpha particle consists of two protons and two neutrons, resembling a helium nucleus.
Emitted via alpha decay.
4C:
List some of the properties of “alpha decay.”
: They are relatively heavy with an atomic mass of 4.
: They travel 5%-7% of the speed of light and are not penetrating particles.
4C:
Why does alpha decay occur?
Alpha decay will occur when there are too many protons in a nuclei, which is the reason for the instability in the first place.
4C:
Define “beta plus decay.”
Beta plus decay entails unstable nuclei decaying into a more stable isotope through the emission of a positron and a neutrino, whilst also transforming a proton into a neutron.
Beta plus decay will occur due to an excess of protons in the nuclei.
4C:
Define “beta minus decay.”
Beta minus decay entails unstable nuclei decaying into a nucleus which is more stable through the emission of an electron and an anti-neutrino, and via the transformation of a neutron into a proton.
Beta minus decay results from nuclei having too many neutrons per proton to achieve stability.
4C:
List some of the properties of beta radiation.
: Beta particles are incredibly light.
: Beta particles travel at quick speeds-90% the speed of light.
: Beta particles have extreme penetrating powers.
4C:
Define “Gamma decay.”
Gamma decay occurs when a nucleus is in an excited state of energy and decays into more stable nuclei (note there is no change between the parent nuclei and the daughter nuclei) through the emission of gamma radiation.
4D:
Define “radiation.”
The transmission of energy from one location to another though EM radiation or high-speed particles.
4D:
Define a “tissue.”
A tissue is a group of specialized cells.
4D:
Define “Ionization.”
Ionization is defined as the process of an electrically neutral atom becoming charged due to the gain or loss of an electron.
4D:
Define “ionizing impact.”
The ionizing impact is defined as the ability of ionization to damage cells.
4D:
Compare the ionizing abilities of Alpha radiation when absorbed from outside and within the body.
When alpha radiation is absorbed from outside the body it has no ionizing impact, as alpha particles cannot penetrate the skin due to their mass.
However, when alpha radiation is absorbed from within the body it can have great levels of ionizing impact.
4D:
Compare the ionizing abilities of Beta radiation when absorbed from outside and within the body.
When Beta radiation is absorbed from outside the body there is a level of ionizing ability on surface-level tissues like eyes, as Beta particles can penetrate the skin.
However, when Beta radiation is absorbed from within the body there is a greater level of ionizing impact.
4D:
Compare the ionizing abilities of Gamma radiation when absorbed from outside and within the body.
When Gamma radiation is absorbed from outside the body it has high levels of ionizing impact due to its extreme powers of penetration.
However, when Gamma radiation is absorbed from within the body it has no ionizing impact as it will pass out un-deflected due to its penetrating powers.
4D:
Describe the capacity for Alpha particles to cause cell damage.
Alpha particles will impact a small range of cells when absorbed within the body. However, due to their extremely high levels of Ionizing impact, they will cause cells to be killed.
4D:
Describe the capacity for Beta particles to cause cell damage
Beta particles will impact a larger range of cells than Alpha particles absorbed. However, their ionizing impact is less than that of Alpha particles but still high, meaning they will cause cell damage and potentially death.
4D:
Describe the capacity for Gamma radiation to cause cell damage.
Gamma radiation passes through the body mostly un-deflected due to its extreme powers of penetration. Hence, its ability to cause cell damage is low, meaning only minimal damage will be done to cells.
4D:
Define the “absorbed dose.”
The absorbed dose measures the radiation absorbed per unit of mass of a tissue and is measured in Gray (GY).
4D:
Define the “equivalent dose.”
The equivalent does measures the energy absorbed and takes into account the type of radiation and its damage on the human body.
It reflects the biological damage on a tissue due to the absorption of a particular type of radiation. Measured in SV.
4D:
Define the “radiation weighting factor.”
The radiation weighting factor shows the biological effect of each type of radioactive decay on the human body.
Alpha decay: 20
Beta decay (Plus and minus): 1
Gamma decay: 1
4D:
Define the “effective dose.”
The effective dose measures the energy a tissue absorbs and reflects the sensitivity of different organs to radiation from the nucleus. It is measured in SV.
4D:
Define the “tissue weighting factor.”
The tissue weighting factor shows the sensitivity of different organs to the absorption of radiation from the nucleus.
4D:
Explain how Alpha radiation is used in medical therapies
This process is known as “targeted alpha decay,” and entails alpha compounds entering the human body and emitting alpha particles, which kill damaged cells and stop them from reproducing.
4D:
Explain how Beta radiation is used in medical therapies.
Sources of Beta decay are placed in “radioactive seeds,” and these seeds enter the human body in affected areas. Given Beta particles can penetrate, they will damage the affected cells they’re placed near.
4D:
Explain how Gamma radiation is used in medical therapies.
Gamma rays emitted via Gamma decay have extreme powers of penetration and speed, meaning they are used for the imaging of impacted areas as they can travel through the body without deflection and not cause damage to cells.
