Term
| Most of the Radioactivity that we personally encounter? |
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Definition
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| Almost all of the helium stoms on earth were originally _______ ejected from radioactive elements. |
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Term
Alpha Particals have an elecric charge of? Beta particals have a charge of? Gamma rays have a charge of? |
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Definition
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Term
| When a radioactive nucleus emits an alpha particle, it's mass numer ________ and it's atomic number________. |
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Definition
decreases by 4 decreases by 2 |
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Term
| When a rodioactive nucleus emits a beta particle, its mass number _______ and its atomic number _______. |
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Definition
doesn't change increase by 1 |
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Term
When a radioactive nucleus emits a gamma ray, its mass number ______ and its atomic number _______. |
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Definition
Doesn't change Doesn't change |
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Term
| Different isotopes of an element have the same numbers of _______, but different numbers of _____. |
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Definition
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Term
| Smaller atoms are usually more stable than larger atoms becasue in a small nucleus the attractive ______ force is greater than the repulsive ______ force. |
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Definition
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The strong nuclear force is a ______ force that pushes apart all protons in the nucleus. |
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Definition
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Term
| The electric force is a _______ force that pushes apart all protons in the nucleus. |
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Definition
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Term
| In general, the larger the nucleus, the greater its ______. |
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Definition
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Term
| A radioactive element can transmute into a different _____ during radioactive decay. |
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Term
| When Uranium-238 emits an alpha particle, we get a nucleus of? |
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Definition
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| When Uranium-239 emits a beta particle, we get a nucleus of? |
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Definition
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Term
| All uranium will eventually decay to _____ through a series of alpha and beta decays. |
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Term
The amount of time for the half the atoms in a radioactive sample to decay is called? |
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Definition
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Term
| The more stable the nucleus the ___ its half-life. |
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Definition
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Term
| The half life of a iven isotope can/cannot be altered by heat, pressure, or some other physical means. |
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Definition
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| The longer and animal is dead, the less/more radioactive carbon-14 it contains relative to the constant amount of non-radioactive carbon-12. |
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Definition
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Term
| Carbon-14 is produced in the atmosphere by? |
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Definition
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| Carbon-14 dating is used to estimate the age of ___ material that was once living. |
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Term
What is the equation for the alpha decay of u-238? |
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Definition
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Term
| What is the equation for the alpha decay of Th-230? |
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Definition
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Term
What is the equation for the alpha decay of Rn-222? |
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Definition
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Term
What is the equation for the beta decay of Pb-214? |
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Definition
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Term
| What is the equation for the beta decay of Bi-210? |
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Definition
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Term
| A 100 gram sample of 16N decays to 12.5 grams in 21.6 seconds. What is its half life? |
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Definition
100-50-25-12.5=3 half-lives 3 half-lives = 21.6 seconds 1 half-life = 21.6/3 7.2 Seconds |
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Term
| The isotope cesium-137, which had a half-life of 30 yrs, is a product of nuclear power plants. How long will it talke for the isotope to decay to about1/16th of its original amount? |
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Definition
1/16 = 1/24 or 4 4 = 4x30 = 120 120 years |
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Term
| How much of 200 g sample of Au-198 is left after 8.1 days if its half life is 2.7 days? |
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Definition
8.1 days = 8.1/2.7=3 3 = 1/23 of 200g = 1/8 x 200g = 25 grams |
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Term
| You have 1 kg of radioactive material which has a half life of 1 year. After 6 years, what fraction of radioactive material will remain? |
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Definition
| 6 yrs = 6 half lives = 1/26 =1/64 |
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