Mrs. Horne's Science Site



Unit 13 - Nuclear ChemistryLesson 1Recall, we learned ___________________________.A _______________ is the nucleus of a _________________________________.The radioactive nuclide strontium-90 has ______________________________. The atomic number is ________.The nuclei of ________________________ gain stability by _________________________________________________ (radiation)Nearly all isotopes with atomic number of ___________________________ are unstable.TransmutationThe conversion of ___________________________ is transmutationArtificial Transmutation – particles ________________________________________________ forcing a change.Natural Transmutation – the nucleus of an atom ____________________________________ due to an__________________________ between the number of ________________________________ in a nucleus. Unstableatoms will decay until they _______________________________________.Mass Defect (Deficit)Some of the mass in the nucleus can be ________________________________ (less than the mass of an ____________)Shown by a very famous equation!In all _______________________ reactions, some amount of mass is ______________________________ into energy.Difference between the mass of an atom and the mass of its individual particlesNuclear Reactions vs. Normal Chemical ChangesNuclear reactions involve the ___________________. The nucleus opens, and_________________________________________________.The opening of the nucleus ___________________________________that holds the nucleus together – called______________________ energy“Normal” Chemical Reactions ________________________________, not protons and neutrons, therefore,comparatively ___________________________ is gained from these reactions.Types of RadiationAlpha (?) – a _______________________________Beta (β) – a.k.a. _____________________________Gamma (γ) – ____________________; called a _____________ rather than a particle – has _______________________Other Nuclear ParticlesNeutron Positron – a positive _____________________, same size as _______________________Proton – usually referred to as ___________________________And many other _________________________Charge of Radiation TypesAlpha particles have a __________________, and beta particles have a ___________________. Both aredeflected by an _______________________________.Gamma rays are ___________________________ and have _____________________, so they are _________________.Penetrating AbilityBehavior of RadiationSince alpha particles have the _____________________, they are the ____________________ type of radiation.Gamma rays move at _______________________________ since they are electromagnetic radiation.Alpha RadiationAn _________________________ (?) or _____________________ (42He) is emittedEach particle contains ___________________________ and has a ____________________ (not usually written)Note that the equation is balanced. The sum of the _______________________________________________________ are equal.Beta RadiationA _____________________ (β) or ___________________________ (0-1e) is emittedA neutron breaks apart into a ____________________, which remains in the _______________, and an___________________, which is ________________________Note that the equation is balanced. The sum of the ________________________________________________ are equal.Gamma RadiationA __________________________ (γ) or ___________________________________ is emitted (light)Gamma rays have __________________, no ____________________________ so they do not alter atomic mass or atomic number. It is _____________________________ which explains the large penetrating power of γ rays.They are often emitted __________________________________ particles Electron CaptureA few large, unstable nuclides decay by __________________________. A heavy, positively charged nucleus________________________________.The electron combines with a _______________________________________________________.Lead-205 decays by electron capture.Balancing Nuclear ReactionsThe total of the _____________________________ (__________________) on the left side of the equation mustequal the sum of the _________________________ on the right side.The total of the ________________________ (_______________________) on the left side of the equation mustequal the sum of the ________________________ on the right side.After completing the equation by writing ________________________________________, a_________________may be necessary to balance the reaction.Use a ___________________________ to fill in the missing _________________________________.Practice ProblemWrite the nuclear equation for the alpha decay of gold-185.Practice ProblemFill in the blank.Practice ProblemFill in the blank.Practice ProblemWhat radioactive isotope is produced in the following bombardment of boron? Lesson 2FissionSplitting a nucleus into ________________________________________________________________.1 g of 235U = Chain reaction - _____________________________________________________________________Critical mass - ______________________________________________________________________Fission and the Atomic Bomb – two masses are kept apart ________________________. When combined they create acritical mass and______________________________________________________.Fission Nuclear ReactorsShearon Harris, like all reactors that supply us with electricity, is a ___________________ reactor.Shearon Harris operates using uranium rods enriched to 3% U-235, but controls the rods from reacting tooquickly by ______________________________________________________________________________Nuclear WasteSpent rods ___________________________________________________________________________Some products, though, are ___________________________________________ and must be safely stored forapproximately 20 ______________________ (thousands of years)FusionCombining of two nuclei to form one ___________________________________________ Thermonuclear reaction - _____________________________________________________________1 g of fusion fuel = ______________________ of coalOccurs naturally in _________________________Fusion in the sunSupplies the earth with nearly _________________________________________________________Sun will eventually __________________________________________________________________Fusion Nuclear ReactorsLike “mini” _____________________Need tons of energy to _____________________________________________________________Currently not sustainable but ________________________________________________________Fission vs FusionFission235U _______________________Danger of ___________________Toxic _______________________Thermal _____________________FusionFuel ______________________No _______________________No _______________________ Not _______________________Uses of RadiationFood _________________________ radiation is used to ___________________________ and ______________________________ of foodIrradiated milk has a shelf life of ____________________________________________________________.USDA has approved irradiation of ______________________________________________.Radioactive TracersExplore _____________________________________Trace _______________________________________Study _______________________________________Radiation treatmentIodine-131 is used to measure _______________________________.The gas xenon-133 is used to ______________________________________________.Iron-59 is used to ________________________________________.Larger doses ___________________________________Internal _______________________________________Dangers of Radiation Radiation ___________________________________ found in biological tissue. This causes ________________ that can disrupt mitosis and normal cell function.Can cause various types of ___________________ in the exposed individual If mutations occur in the ________________________________________ they may be passed on to the offpsringHalf-LifeThe time required for one half of the nuclei of a radioisotope sample to ___________________________________________________________________ .Every half-life, the mass of a sample ___________________________________________ .Formula:m = mass after decayt = timem0 = original massh = half-lifeThus, # half-lives = ___________________-Practice ProblemCarbon – 14 emits beta radiation and decays with a half-life of 5730 years. Assume you start with a mass of 2.00 x 10-12 g of carbon – 14. How many grams of the isotope remain after 17,190 years?Practice ProblemWhat is the half life of a radioisotope if a 12 gram sample decays into a 3 gram sample over a period of t = 25 years? ................
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