TLO 4 Nuclear Stability Flashcards
ELO 1 As it applies to radioactive decay, describe the Conservation of Electric Charge.
Charges are neither created nor destroyed.
It is possible for a neutron to become a proton and vice-versa with emission of a beta particle.
Beta- particle for neutron-to-proton,
Beta+ particle for proton-to-neutron.
ELO 1 As it applies to radioactive decay, describe the Conservation of Mass Number.
There is no net change in the number of nucleons.
The conversion of one type of nucleon to another is allowed.
ELO 1 As it applies to radioactive decay, describe the Conservation of Mass and Energy.
The total of the kinetic energy and the energy equivalent of the mass in a system must be conserved in all decays and reactions.
Mass can be converted to energy and vice-versa, but the sum of mass & mass-equivalent energy must be constant.
ELO 1 As it applies to radioactive decay, describe the Conservation of Momentum.
The total amount of momentum is the same before and after the reaction, even though it might be distributed differently among entirely different nuclides and/or particles.
ELO 2 Describe Alpha Decay
The emission of alpha particles (helium nuclei).
Results in atomic number being reduced by 2 due to emitting 2 protons and the amu being reduced by 4 (2 protons + 2 neutrons emitted).
ELO 2 Describe Beta Minus Decay
Negative electron emission - from the conversion of a neutron to a proton. Increases the atomic number by 1 (neutron-to-proton), but leaves mass number unchanged (only electron was released - negligible mass)
ELO 2 Describe Beta Plus Decay
Positron emits from the conversion of a proton into a neutron. The atomic number decreases by 1 (proton-neutron conversion) and mass number is unchanged (only a positive electron was emitted - negligible mass)
ELO 2 Describe Electron Capture
Nuclei with excess protons capture an inner orbit electron that immediately combines with a proton to form a neutron and a neutrino.
X-rays are emitted when an electron from another shell fills the vacancy in the K-shell.
ELO 2 Describe gamma ray emission
High-energy electromagnetic radiation originating in the nucleus emitted in the form of a photon.
An excited nucleus drops to the ground state by emitting gamma radiation.
ELO 2 Describe Internal Conversion
A circumstance where, when an excited nucleus is emitting a gamma ray, the gamma ray interacts with one of the innermost orbital electrons, transferring the gamma’s energy to the electron which ejects the electron from the atom.
As a result of the K-shell vacancy, an electron from another shell fills the vacancy which emits an X-ray.
ELO 2 Describe Isomeric Transition
Particle emission occurs, but the nucleus remains in an excited state for a measurable time before going to ground state. A nucleus is said to be in isomeric transition during this measurable time period.
ELO 2 Describe Neutron Emission
When unstable nuclei emit neutrons to become more stable.
ELO 3 Given the Stability Curve from the Chart of the Nuclides, determine the type of radioactive decay a nuclide will typically undergo.
Nuclides below and to the right of the line of stability undergo Beta minus decay.
Nuclides above and to the left of the line of stability undergo either Beta plus decay or electron capture.
Nuclides in the upper right hand region are likely to undergo alpha decay.
ELO 3 On the Chart of the Nuclides, explain in which direction a nuclide will decay.
Toward the Line of Stability
ELO 4 Describe the radioactive decay chain for a nuclide.
When an unstable nucleus decays, the resulting daughter nucleus is not necessarily stable. If unstable, the daughter nucleus undergoes additional decay. The decay chain is the sequence from the original unstable nuclide, through the intermediary nuclide(s) to the final stable nuclide.
