## Nuclear Energy Unit One Test

 John Dalton
 Thought up the Solid Sphere Model.  It could not be divided.
 Proton
 Located in the nucleus Atomic mass of 1 Positive Charge
 Electron
 Located in circulation around the nucleus Has almost no atomic mass Negative Charge
 Neutron
 Located in the nucleus Atomic mass of 1 Nuetral charge (no charge)
 Atomic Number
 Number of protons in an atom
 Atomic Mass
 Mass of protons and neutrons   Example:  3 protons + 7 neutrons = Atomic mass of  10
 How do you use the periodic table?  Example: 1 H Hydrogen 1.00794
 1           <—-Atomic Number H                        <—-Symbol Hydrogen                         <—-Name 1.00794   <—-Average Atomic Mass
 Isotope
 Different forms of an element Different isotopes contain different numbers of neutrons
 Average Atomic Mass
 Average mass from a series of samples
 Calculating Average Atomic Mass Example: Carbon 12:  98.9% Carbon 14:  1.1%
 98.9% * 12 / 100 = 11.868 1.1% * 14 / 100 = .154   11.868 + .154 = 12.022   Average Atomic Mass = 12.022amu
 Calculating Alpha (α) Decay Example:   Pu240 94
 Top number: Atomic Mass Bottom Number: Atomic Number Alpha decay causes atoms to lose 2 neutrons and 2 protons Answer: Pu240 94 —-α—-> U23692 + He42
 Calculating Beta (β) Decay Example:    Po20984
 Beta decay causes neutrons to lose their electron. This leaves only the proton Atomic Mass doesn’t change, but the Atomic number goes up Answer Po20984 —β—> At20985 + β0-1
 No particles are disturbed during gamma ray radiation There is only a loss of energy Answer: Rn22286—γ—> Rn22286 + γ 00
 Half Life
 Amount of time it takes for 50% of a sample to decay into something else Once half is gone, the remaining portion is cut by half, and so on 1 –> ½ –> ¼ –> etc. Link to see what half life looks like: http://www.kgs.ku.edu/Extension/gifs/halflife.gif
 Nuclear Fission
 The splitting of an atom
 Chain Reaction
 When a fast moving neutron hits an atom’s nucleus, the nucleus splits and releases 3 neutrons that in turn will hit the nuclei of 3 other atoms Let us write you a custom essay sample on Nuclear Energy Unit One Test For Only \$13.90/page ORDER NOW   Example Link: http://www.planetseed.com/files/uploadedimages/Science/Earth_Science/Global_Climate_Change_and_Energy/Related_Articles/nuclear1(2).jpg
 Enriched Uranium How much is needed in nuclear bombs? Power plants?
 Uranium that is filtered to a specific amount of U-235 , the rare isotope Bombs require at least 80% enriched uranium Power Plants require 2-3% at most
 Control Rods
 Movable Absorb neutrons released by fission Slow down reaction
 Moderator
 Absorb heat from reaction Usually graphite Slow down neutrons
 Fuel Rods
 Contain 2.5cm pellets of uranium Spent nuclear fuel is a problem because it is still radioactive (emits α, β, and γ radiation)
 Pros of Nuclear Power
 Some examples: No greenhouse gases Needs very little uranium Large uranium deposits in Canada and Australia A single power plant creates huge amounts of energy
 Cons of Nuclear Power
 Some Answers: Radioactive Waste Not much uranium in the world Safety risks to the general public: Potential radiation exposure or explosion (melt down) if there is an accident
 J. J. Thomson
 Put magnets on either side of the Cathode Ray tube, found that the ray going through the tube was negatively charged (the ray curved towards the positive magnet) Came up with the plum pudding / chocolate chip cookie model Site for Cathode Ray Tube Diagram http://hep.physics.indiana.edu/~hgevans/classes/graphics/em/crt.gif
 Ernest Rutherford
 Gold Foil Experiment (Shoots α particles at gold foil.  Most particles go through, some are repelled, others turn completely around) Came up with nuclear and proton models of the atom Gold Foil Experiment Diagram http://www.rsc.org/chemsoc/timeline/graphic/1911_gfoil_02.jpg Nuclear Model of the Atom http://www.faqs.org/docs/qp/images/rfmodel.gif Proton Model of the Atom http://www.aplusphysics.com/courses/regents/modern/images/atom_diagram.png
 Neils Bohr
 Didn’t do many experiments, but had a problem with Rutherford’s nuclear model Came up with a solution as to why electrons from nuclear model don’t crash into the nucleus: they have a set track!  High energy neutrons are further away from the nucleus, while low energy electrons are close to the nucleus Solar System Model: http://wiki.nisk.k12.ny.us/groups/84physicalscience/wiki/4ee4b/images/af20c.gif
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