Henry County School District



Name: ________________________________Date: ______________________Period: ___Chapter 10 Nuclear Chemistry Guided Notes10.1 Radioactivity____________________ is the process in which an ____________________ atomic____________________ emits ____________________ particles and energy.____________________ is short for radioactive isotopes, which is any atom containing an unstable nucleus.Radioisotopes spontaneously ____________________ into other isotopes ____________________ ____________________ and is said to undergo nuclear ____________________ .During nuclear ____________________, atoms of one element can change into atoms of a different ____________________ altogether. Types of Nuclear Radiation____________________ ____________________ is charged particles and energy that are emitted from the nuclei of radioisotopesCommon types of nuclear radiation include alpha particles, beta particles and gamma rays Alpha Decay____________________ ____________________ is a positively charged particle made up of two protons and two neutrons (the same as helium ____________________)Alpha particles are the ____________________ ____________________type of nuclear radiation.They can be ___________________ by a sheet of paper or by ____________________,The alpha particle has no electrons so it has a _____________________._____________________is the symbol for an alpha particleAlpha Decay expressed as an chemical equationBeta Decay_____________________ _____________________is an electron emitted by an unstable nucleusBeta particles are abbreviated ________________ or __________________Beta particles are ___________________penetrating than alpha particles.Beta particles pass through paper but can be stopped by a ________________ sheet of__________________The beta particle has no _____________________ During beta decay a neutron decomposes into a proton and an electronThe proton stays trapped in the nucleus while the ___________________is __________________Gamma Decay_________________ ________________ is a penetrating ray of energy emitted by an unstable nucleus.The symbol for a gamma ray is _____________ The gamma radiation has ___ __________________ and ____ _________________During gamma decay the atomic number and mass number of the atom remain the same but the energy of the nucleus decreasesGamma decay often accompanies alpha or beta decay.Gamma rays have the ___________________ ____________________ of the three, 2371725432435gamma rays can pass through paper and aluminum but is stopped by thick concrete or ___________________Comparing strength of Nuclear RadiationSummary of Nuclear radiation ParticlesAlpha ParticlesSymbol _______________2 protons & 2 neutrons Has a charge ___________ and mass of 4 atm_______________Stopped by _______________Beta ParticlesSymbol _____________An _______________Has no _______________Stronger than AlphaStopped by sheet of _______________Gamma RaySymbol _______________Only _______________ No mass, No charge _______________Stopped by thick lead or thick _______________10.2 Rates of Nuclear Decay_______________ _______________is the time required for one _______________of a sample of radioisotope to _______________After one half-life, half of the atoms in a sample have decayed, while the other half remains unchanged. Half-lives can vary from fractions of a second to billions of yearsTime in which ? of the original isotopes decayFirst Half-life _____________original isotopes remain? decayedSecond Half-life _____________ original isotopes remain? decayedThird Half-life _____________ original isotopes remain7/8 decayedUnlike chemical reaction rates, which vary with the conditions of a reaction, nuclear decay rates are constant. Half-Life progression of Iodine-131, 100 gram sample Days: _____Gram: _____Days: _____Gram: _____First half lifeDays: _____Gram: _____Second half lifeDays: _____Gram: _____Third half lifeDays: _____Gram: _____Fourth half life Days: _____Gram: _____Fifth half lifeHalf life PracticeIf we start with 400 atoms of a radioactive substance, how many would remain after one half-life?_________ after two half-lives? _________ after three half-lives? _______2. If we start with 48 g of a radioactive substance with a 2 hour ? life , how much is left after two half-lives? _____ after four half-lives?___ how much time has passed for 4 ? lives? ______If we start with 16 grams of a radioactive substance that has a 6 day ? life, How much will remain after three half-lives?________ How much time would have passed?_______How long is a half-life for carbon-14?________ If only 25% of the carbon-14 remains, how old is the material containing the carbon-14? ___________ If a sample originally had 100 grams of carbon-14, how many atoms will remain after 16,110 years? _______10.4 Fission and Fusion_______________ _______________ force is the attractive force that binds protons and neutrons together in the nucleus. Over very short distances the strong nuclear force is much great than the electric forces among protons. The affect of size on Nuclear ForceThe _______________the number of protons in a nucleus the greater is the electric _______________ that repels those protons.In larger nuclei, the repulsive electric force is s_______________ than in_______________nucleiLarger numbers of electric forces make larger nucleus less stable Unstable NucleiA nucleus becomes unstable (_______________) when the strong nuclear force can no longer overcome the repulsive electric forces among protons.All nuclei with more than _____________ protons are _______________Fission_______________ is the _______________ of an atomic nucleus into two smaller parts.In nuclear fission, tremendous amounts of _______________ can be produced from very _______________ amounts of mass. A chain reaction refers to a process in which neutrons released in fission produce an additional fission in at least one further nucleus. This nucleus in turn produces neutrons, and the process repeats. The process may be controlled (nuclear _____________) or uncontrolled (nuclear ______________). Critical MassThe minimum amount of a substance that can sustain a chain reaction. It takes very little Uranium-235 to reach critical mass.Fusion_______________ is a process in which the nuclei of two atoms _______________ to form a _______________nucleus.During fusion a small fraction of the reactant _______________ is converted into _______________.Inside the sun an estimated 600 millions tons of hydrogen undergo fusion each secondFusion requires extremely high temperatures (10,000,000?C).At these temperature matter can exist as plasma_______________ is a state of matter in which atoms have been stripped of their _______________Fusion reactions produce much more _______________ per gram of fuel and produce _______________radioactive _______________ than fission.Two main problems in designing a fusion rector 1st they need to achieve _______________ temperatures required to start the reaction It requires a heat of about 10 million degrees Celsius. Scientist have to find a way of producing and containing that much heat. 2nd they must contain the _______________Fusion can occur only in the plasma state of matter (super-heated gas). Compare/contrast Fission and FusionFission_______________ a larger atom into smaller atomsReleases two or three neutronsReleases large amounts of _______________Used as a source for _______________Fusion_______________ small atoms into a larger atomRequires very high temperaturesReleases large amounts of_______________Not currently a valid source of electricityNuclear Energy From FissionNuclear power plants generate about _______________of the electricity in the USNuclear power plant do _______________ emit air _______________But workers are made to wear protective clothing to reduce their exposure to nuclear radiation.Nuclear power plants _______________ _______________waste that must be isolated and stored so that it does not harm people or the environment.If the reactors cooling systems failed a _______________ might occurDuring a meltdown the core of the reactor melts and radioactive material may be released.Nuclear Power Fission and FusionFission235U is limiteddanger of meltdowntoxic wastethermal pollution FusionHydrogen is abundantno danger of meltdownno toxic wastenot yet sustainableDangers – nuclear _______________Nuclear _______________Benefits – Medical_______________ TreatmentRadioactive tracersNuclear _______________Other Uses of RadiationIrradiated Food (p.676)Radioactive Dating (p.683)Nuclear Medicine (p.692-693) ................
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