Chemistry Unit 4 Test (Nuclear Chemistry) – Flashcards
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Alpha decay
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-emits a helium nucleus (4/2 He) -High ionizing power -Low penetrating power -Example: 222/86 Rn → 218/84 Po + 4/2 He
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Beta decay
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-Emits an electron (0/-1 e) (neutron breaks into proton and electron) -Moderate ionizing power -Moderate penetrating power -Example: 42/19 K → 42/20 Ca + 0/-1 e
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Gamma decay
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-Emits an electromagnetic, short wavelength photon (0/0 y) -Low ionizing power -High penetrating power -Example: 222/86 Rn → 146/53 I + 86/33 As + 0/0 y
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Positron emission
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-Emits a positively charged electron (0/+1 e) -Moderate ionizing power -Moderate penetrating power -Example: 30/15 P → 30/14 Si + 0/+1 e
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Radioactivity
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The emission of tiny, energetic particles by nuclei of certain atoms
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Why does an atom undergo radioactive decay?
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It is unstable
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What makes an atom radioactive?
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The atom having a large difference between the amount of neutrons and the amount of protons
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Applications of nuclear chemistry
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Nuclear medicine -Cancer treatment (radiation) -Isotope scanning (find infected organs) -Radiotherapy Agriculture Carbon-dating
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Fission
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-The splitting of atoms -Gives off high amounts of energy -Most commonly used -Used in nuclear power plants
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Fusion
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-The combination of two light nuclei -Gives off high amounts of energy -Not necessarily neutron-induced -Not used due to its need of very high temperatures -Occurs on the sun
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A
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mass number
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Z
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atomic number
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Film-badge dosimeters
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Collects radioactive particles when they pass through the photographic film (analyzed later)
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Geiger-Muller counter
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Emitted radioactive particles put in an Argon chamber make a "click"
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Scintillation counter
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Radioactive emissions pass through a gas and produces light
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Half-life
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Amount of time it takes for a radioactive isotope to decay to half of its original mass
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Half-life equation
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total time ÷ half-life time = number of half-lives
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Half-life application
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Radon in homes
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Nuclear reactions
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Occur in the nuclei of unstable atoms
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Chemical reactions
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Occur between the electrons of atoms
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Radiocarbon dating
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-Use of naturally occurring elements in our environment to estimate the ages of fossils and artifacts -Most used is the beta decay of Carbon-14 into Nitrogen-14 -Carbon-14 is constantly consumed by all forms of life -Organism stops consuming Carbon-14 right at death
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Half-life of Carbon-14
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5730 years
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rem
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(Roentgen equivalent man) Is a weighted measure based on ionizing power
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Effects of radiation
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*Dependent on amount (severity)* -~20 rem: decreased white blood cell count -~100+ rem: increased cancer risk -~500+ rem: death
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Types of radiation / effects
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Acute: Caused by larger amount in less time Cancer Risk: Caused by lower dose over a longer time Genetic Defects: Caused by a pregnant mother being exposed to radiation
