Radioactivity Flashcards
Why do positive charges stay close together in the nucleus?
The nuclear force
What are the properties of the nuclear force?
Independent of electric charge.
The range of action is very short: residual effect of the force linking quarks.
What hold nucleons in the nucleus together?
The strong nuclear force
What is required to break the nucleus apart?
Energy
How does the stability of the nucleus effect the biding energy required to break it apart?
The more stable the nucleus the greater the binding energy required to break it apart.
Do protons or neutrons stabilize the nuclei?
Neutrons contribute to stabilize the nucleus.
How many protons in a nuclei does it take to make it unstable?
83 protons
What are the three main types of ray produced when an unstable nucleus disintegrates spontaneously?
Alpha, Beta, Gamma
What is transmutation?
When one element is converted into another e.g. an alpha decay
What happens in a beta (-) decay?
Th neutron decays into a proton, electron and a antineutrino
What happens in a Beta (+) decay?
A proton decays into a neutron, a positron and a neutrino
What happens in a Gamma decay?
When a nucleus changes from a an excited energy state to a lower energy, a photon is emitted called a gamma ray.
Do isolated protons decay?
No
Do isolated neutrons decay?
Yes, in about 15 minutes.
What kind of process is a radioactive decay?
A probabilistic process
What is the Activity?
The average number of disintegrations per second.
What is Activity measured in?
Becquerel (Bq)
What is the half life?
The time taken in which one half of the radioactive nuclei disintegrate.
What can be compared to find the age of an object?
The current Activity and the initial Activity
