Nuclear Structure & Decay Flashcards
(26 cards)
Higher Z elements are relative more neurton rich or proton rich?
neutron rich
Which nuclei Z of elements are unstable and has no stable form?
Nuclei with Z > 83
What is an example of beta minus decay?
32P –> 32S (Z of P is 15 and becomes 16 and then P turns into S)
Does Beta-minus decay happen to neutron-rich or neutron-poor?
Neutron-rich
Does Beta-plus decay happen to neutron-rich or neutron-poor?
Neutron-poor
Draw the types of decay with x-axis is the # of protons and y-axis is the # of neutrons
beta minus decay takes place for isotopes that are relatively neutron-rich. How are they made?
In a nuclear reactor
beta plus decay takes place for isotopes that are relatively neutron-poor. How are they made?
They are produced in cyclotrons where a target is bombarded with a heavy charged particle such as a proton.
Give a specific exampl of beta plus decay
18F –> 18O + B+ (positron)
What nuclei undergo alpha decay?
particularly heavy ones
What other decay modes are there (other than beta, alpha decay)?
- electron capture
- isomeric transition
- internal conversion
What is electron capture?
an inner-shell electron interacts witht the nucleus and the result is that a proton is lost.
Provide a specific example of electorn capture?
125I –> 125mTe (tellurium in a metastable state)
What is isomeric conversion?
Transition in which a nucleus in an excited state transitions to the ground state and a photon is emitted.
There is no change in Z.
What happens in the electron capture specfiically with 125 I?
125 I (iodine) decays into 125mTe (tellurium) in a metastable state, which is a high energy state of the nucleus that lasts for a long time but eventually decays into a ground state.
After an electron capture, what happens?
There is a vacancy in an inner shell electron and an outer shell electron can transition into this state, producing a characteristic photon.
Auger electron can also be emitted.
Describe the below parameters in electron capture
1) Z
2) Types of particles emitted
Z decreases (since a proton is lost by interacting with an electron)
Types of particles emitted: gamma ray, Auger electrons, Alpha particle
What happens to Z value in beta-minus decay?
Z increases (consider both electron and proton are lost and proton is being added to the nucleus)
What happens to Z value in beta-plus decay?
Z decreases
How does Z value chance in alpha decay?
Z –> Z-4 ?
What is internal conversion?
Conversion in which an excited nucleus transitions to the ground satate, however, instead of emitting a photon, an electron is ejected.
The energy of the ejected electron is the energy of the transition (which would have been a photon) minus the binding energy of the electron.
There is no change in Z.
How does Z value changen in isomeric transition?
No change
How does Z value changen in internal conversion?
No change in Z.
What are the main particles emitted in isometric transition?
Gamma ray in the form of photon
