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Known nuclides PROPERTIES OF FUNDAMENTAL PARTICLES Particle Symbol Charge Mass (x10 -19 Coulombs) (x10 -27 kg) Proton P +1.60218 1.672623 Neutron N.

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Presentation on theme: "Known nuclides PROPERTIES OF FUNDAMENTAL PARTICLES Particle Symbol Charge Mass (x10 -19 Coulombs) (x10 -27 kg) Proton P +1.60218 1.672623 Neutron N."— Presentation transcript:

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3 Known nuclides

4 PROPERTIES OF FUNDAMENTAL PARTICLES Particle Symbol Charge Mass (x10 -19 Coulombs) (x10 -27 kg) Proton P +1.60218 1.672623 Neutron N 0 1.674929 Electron e -1.60218 0.0005486

5 NUCLEAR STABILITY Modes of Radioactive Decay Alpha Decay - Heavy Isotopes - 4 2 He +2 -  Beta Decay - Neutron Rich Isotopes - e - -   Positron Emission -Proton Rich Isotopes -   Electron Capture - Proton Rich Isotopes x - rays Gamma-ray emission(  - Decay of nuclear excited states Spontaneous Fission - Very Heavy Isotopes

6 Alpha Decay -Heavy Elements 238 U 234 Th +  + E T 1/ 2 = 4.48 x 10 9 yrs 210 Po 206 Pb +  + E T 1/ 2 = 138 days 256 Rf 252 No +  + E T 1/ 2 = 7 msec 241 Am 237 Np +  + E T 1/ 2 = 433 days

7 Beta Decay - Electron Emission N P + +   + Energy 90 Sr 90 Y +   + Energy T 1/ 2 = 30 yrs 14 C 14 N +   + Energy T 1/ 2 = 5730 yrs 247 Am 247 Cm +   + Energy T 1/ 2 = 22 min 131 I 131 Xe +   + Energy T 1/ 2 = 8 days

8 Natural Decay Series of Existing Isotopes 40 K 40 Ar T 1/2 = 1.29 x 10 9 yrs 232 Th 208 Pb T 1/2 = 1.4 x 10 10 yrs 235 U 207 Pb T 1/2 = 7 x 10 8 yrs 238 U 206 Pb T 1/2 = 4.5 x 10 9 yrs

9 Figure 21.2: Decay series

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11 Natural Decay series for Uranium 238 238 U 234 Th 234 Pa 234 U 230 Th 226 Ra 222 Rn 218 Po 214 Pb 218 At 214 Bi 210 Tl 214 Po 210 Pb 206 Hg =  decay 210 Bi 206 Tl =   decay 210 Po 206 Pb 238 U -- 8  decays and 6  decays leaves you with -- 206 Pb

12 The decay of a 10.0 -g sample of strontium-90 over time.

13 Accelerator tunnel at Fermilab, a high- energy particle accelerator in Batavia, Illinois. Source: Fermilab Batavia, IL

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16 Plot of energy versus the separation distance

17 Units used for Nuclear Energy Calculations electron volt - (ev) The energy an electron acquires when it moves through a potential difference of one volt: 1 ev = 1.6 x 10 -19 J Binding energies are commonly expressed in units of megaelectron volts (Mev) 1 Mev = 10 6 ev = 1.6 x 10 -13 J A particularly useful factor converts a given mass defect in atomic mass units to its energy equivalent in electron volts: 1 amu = 931 x 10 6 ev = 931 Mev

18 Binding energy per nucleon as a function of mass number.

19 Binding Energy per Nucleon of Deuterium Deuterium has a mass of 2.01410178 amu. Hydrogen atom = 1 x 1.007825 amu = 1.007825 amu Neutrons = 1 x 1.008665 amu = 1.008665 amu 2.016490 amu Mass difference = Theoretical mass - actual mass = 2.016490 amu - 2.01410178 amu = 0.002388 amu Calculating the binding energy per nucleon: Binding Energy -0.002388 amu x 931.5 Mev / amu Nucleon 2 nucleons = =

20 Calculation of the Binding Energy per Nucleon for Iron- 56 The mass of Iron -56 is 55.934939 amu, it contains 26 protons and 30 Neutrons Theoretical Mass of Fe - 56 : Hydrogen atom mass = 26 x 1.007825 amu = 26.203450 amu Neutron mass = 30 x 1.008665 amu = 30.259950 amu 56.463400 amu Mass defect =Actual mass - Theoretical mass: 55.934939 amu - 56.46340 amu = - 0.528461 amu Calculating the binding energy per nucleon: Binding Energy - 0.528461 amu x 931.5 Mev / amu nucleon 56 nucleons = =

21 Calculation of the Binding Energy per Nucleon for Uranium - 238 The actual mass of Uranium - 238 = 238.050785 amu, and it has 92 protons and 146 neutrons Theoretical mass of Uranium 238: Hydrogen atom mass = 92 x 1.007825 amu = 92.719900 amu neutron mass = 146 x 1.008665 amu = 147.265090 amu 239.984990 amu Mass defect = Actual mass - Theoretical mass: 238.050785 amu - 239.984990 amu = - 1.934205 amu Calculating the Binding Energy per nucleon: Binding Energy -1.934205 amu x 931.5 Mev / amu mucleon 238 nucleons = =

22 http://www.pbs.org/wgbh/amex/bomb/sfeature/foxhole.html http://www.atomicarchive.com/Movies/blastwave3.shtml http://www.atomicarchive.com/Movies/mushroomcloud.shtml Oppenheimer http://www.atomicarchive.com/Movies/Movie8.shtml

23 Both fission and fusion produce more stable nuclides and are thus exothermic.

24 Upon capturing a neutron, the 235 U nucleus undergoes fission to produce two lighter nuclides, free neutrons (typically three), and a large amount of energy.

25 Representation of a fission process in which each event produces two neutrons, which can go on to split other nuclei, leading to a self-sustaining chain reaction.

26 If the mass of the fissionable material is too small, most of the neutrons escape before causing another fission event; thus the process dies out.

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28 Nuclear power plant

29 Breeder reactor at a nuclear power plant in St. Laurent-Des Eaux, France. Source: Stock Boston

30 A Uranium "button" for use as a fuel in a nuclear reactor.

31 Schematic of a reactor core


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