Radioactive or unstable
Nuclei that emit some form of radiation. A nucleus that does this is an unstable nucleus.
What determines the stability?
The proton : neutron ratio determines the stability.
If an atom is outside the stability band, it’s…
There are no stable elements beyond atomic # __.
83 (everything beyond Bi is radioactive)
Another word for natural decay
Another word for natural transmutation
Involves the emission of an alpha particle
Emission of a beta particle
Emission of gamma rays
Emission of a positron
Which type of natural decay has the greatest penetrating power?
What happens during positron decay?
Proton converts to a neutron
The amount of time it takes for a given sample of a radioisotope to decay to 1/2 of its original mass.
When a nucleus mutates after being bombarded with a high energy particle.
The splitting of a large nucleus (U-233, U-235, Pu-239) by bombarding the nucleus with a neutron. The results are fragments (?), energy (?), and multiple neutrons (chain reaction).
Joining very light nuclei into a larger nucleus.
Why is fusion extremely difficult?
Fusion is extremely difficult because the positive nuclei repel. Therefore, lots of heat
and pressure is needed.
Uses of nuclear science- energy
-nuclear reactors use fission to produce electricity
Uses of nuclear science- medicine
60^Co -used for radiation therapy for cancer
99^Tc -used to diagnose brain tumors
131^I -used to diagnose thyroid disorders
Uses of nuclear science- tracers
Used to follow chemical pathways
Uses of nuclear science- example of tracer
14^C in photosynthesis
Uses of nuclear science- dating
14^C : 12^C -used to date organic substances
238^U : 206^Pb -geological dating
Uses of nuclear science- food preservation
Radiation kills eggs, spores, bacteria, etc.
Uses electromagnets to accelerate charged particles
E = mc^2
What happens to some of the mass?
Mass is converted into energy