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.
