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ch. 20 sec.1,2,3

Terms in this set (30)

Strong Force
Attractive force that act between protons and neutrons in an atomic nucleus.
Radioactivity
Process that occurs when a nucleus decays and emits matter and energy.
What force holds the atomic nucleus together?
Strong force
How do the strong force and the electric force compare to each other?
Strong force is 100 times stronger than the electromagnetic force.
Electric Force
Force between electric charges such as protons and electrons
Isotope
Same number of protons but different numbers of neutrons.
Atomic Number
The number of protons in a nucleus
Mass Number
The number of protons and neutrons in a nucleus
Why might a nucleus decay?
Due to its neutron to proton ratio
Why do large nuclei tend to be radioactive
Large nuclei are unstable because the nuclear force decreases as protons spread further apart.
Alpha Particle
A particle that is composed of two protons and two neutrons.
Beta Particle
A high-energy electron that is emitted when a neutron decays into a proton
Gamma Rays
Extremely high-energy electromagnetic waves
Transmutation
The process of changing one element into a different element.
Chain Reaction
A series of repeated fission reactions caused by the release of additional neutrons in every fission.
How does nuclear fission differ from nuclear fusion?
Both fission and fusion are nuclear reactions that produce energy, but the applications are not the same. Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy
How are mass and energy related?
Based on Einstein's equation E = mc^2, the amount of energy added is relative to the mass gained by the proton multiplied by the speed of light squared. In other words, a lot of energy is converted into a relatively small amount of mass.
Radioactivity can result in what?
Alpha particles, beta particles, gamma rays
When does a nuclear fission occur?
When a neutron strikes a nucleus, causing it to split into smaller nuclei.
When does nuclear fission occur?
When two nuclei combine to form another nucleus.
A small amount of mass is the same as a tremendous amount of ______
Energy
Contrast alpha particle, beta particle, gamma ray
*Alpha decay forms new element with two fewer protons and two fewer neutrons;
*Beta decay forms new element with one more proton and one fewer neutron.
*Gamma decay forms NO new element, but now the element has less energy because energy is released as gamma rays.
Gamma radiation has the highest penetration power, Beta decay goes the second, alpha decay the last. However, alpha particles make the most damage even if it has the lowest penetration power among the three
Tracer
A radioactive isotope that doctors use to locate molecules in an organism.
Half-life
The amount of time it takes for half the nuclei in a sample of an isotope to decay.
How can radioactivity be detected?
The most common type of radiation detector is a Geiger-Mueller (GM) tube, also called a Geiger counter.
What are some common sources of background radiation?
Cosmic rays - radiation that reaches the Earth from space.
Rocks and soil - some rocks are radioactive and give off radioactive radon gas.
Living things - plants absorb radioactive materials from the soil and these pass up the food chain.
How can radioactivity be used to find the age of an object?
By using radiometric dating
Radiometric Dating
is a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they formed.
What do doctors use as tracers for medical diagnoses as well as to kill cancer cells?
Radioactive Isotopes
Explain why background radiation can never be completely eliminated.
Because there's no way to shield yourself from all of it, and it exists everywhere.
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