chapter 18: radioactivity & nuclear reactions

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Georgia Performance Standards SPS3. Students will distinguish the characteristics and components of radioactivity. a. Differentiate among alpha and beta particles and gamma radiation. b. Differentiate between fission and fusion. c. Explain the process half-life as related to radioactive decay. d. Describe nuclear energy, its practical application as an alternative energy, and its potential problems.

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Chapter 18: Radioactivity & Nuclear Reactions Georgia Performance Standards
SPS3. Students will distinguish the characteristics and components of radioactivity. a. Differentiate among alpha and beta particles and gamma radiation. b. Differentiate between fission and fusion. c. Explain the process half-life as related to radioactive decay. d. Describe nuclear energy, its practical application as an alternative energy, and its potential problems. The Big Idea:RadioactivityEssential Question: What is the ratio of protons to neutrons in each of these isotopes of helium? H-3, H-4 Radioactivity Isotopesatoms of the same element thathave different numbers of neutrons ex: carbon 12, carbon 13, carbon 14 The atoms of all isotopes of an element havethe same number of electrons, and have thesame chemical properties. Radioactivity Marie Curie named the process by whichmaterials gave off rays radioactivity. Radioactivitynuclear decay whichhappens when the strong force is not largeenough to hold the protons and neutronstogether nucleus with too many or too few neutronscompared to protons is radioactive Stable and Unstable Nuclei
Radioactivity Stable and Unstable Nuclei The ratio of neutrons to protons is relatedto the stability of the nucleus. ex: less massive elements = 1:1 heavier elements = ~3:2 However, the nuclei of any isotopes thatdiffer much from these ratios are unstableand therefore are radioactive. Radioactivity Got My Eye on Ions! Lab
Given a substance in which the number ofprotons, neutrons, and electrons are known, howcould it be determined if it is an electrical stableatom, or isotope, or an ion? Create data table. Bag numbers=1-14 Bag Number Number of Protons (brown) Number of Neutrons (white) Number of Electrons (lentils) Ion, Isotope or electrically stable element? Name of Bags Element 1 2 Do NOW: Discuss with you elbow partner: Is the song Radioactive by Imagine Dragons properly titled? Justify your response. Homework Due Monday, Nov. 16Experiment and data collection ends Due Wednesday, Nov. 18data tables and graph(s) Due Friday, Nov. 20conclusion due Georgia Performance Standards
SPS3. Students will distinguish the characteristics and components of radioactivity. a. Differentiate among alpha and beta particles and gamma radiation. b. Differentiate between fission and fusion. c. Explain the process half-life as related to radioactive decay. d. Describe nuclear energy, its practical application as an alternative energy, and its potential problems. The Big Idea:Nuclear DecayEssential Question: Why is it important to know that nuclear decay produces nuclear radiation? Bring one individualized size bag of M&Ms for activity on Tuesday.
Homework Bring one individualized size bag of M&Ms for activity on Tuesday. Discuss the Great Debatereceive role cards. Prepare for your role for the debate on Friday. Nuclear Decay https://www.khanacademy.org/science/chemistry/radioactive-decay/v/types-of-decay In 1896, Henri Becquerel left Uranium saltin a drawer. Later he found the outline ofclumps it leading him to hypothesize thatit emitted radiation. In 1899, Ernest Rutherford discovered thatU compounds produce 3 kinds ofradiation: alpha, beta, andgamma Alpha Particlesmade of 2 protons and 2 neutrons
Nuclear Decay Alpha Particlesmade of 2 protons and 2 neutrons More massive than beta or gamma with the most electric charge Can be stopped by a sheet of paper. Alpha Particles Symbol Mass 4 Charge +2 Nuclear Decay Damage and Uses of Alpha Particles
If released in human body, can damagebiological molecules causing illness anddisease. Smoke detectors give off alpha particles thationize surrounding air, if smoke enters theionized air the alarm goes off. Transmutationthe process of changing oneelement to another through nuclear decay. Nuclear Decay Beta Particles
In an unstable nucleus aneutron decays into aproton and emits anelectron The emitted electron fromthe nucleus is the betaparticle; however, the massnumber stays the same Beta Particles + Symbol 0e __1 Mass 0.0005 Charge Damage and uses of Beta Particles
Nuclear Decay Damage and uses of Beta Particles Pass through paper but stopped by aluminum foil Damage cells when emitted by radioactive nuclei in side the human body. Nuclear Decay Gamma Rays
Electromagnetic waves withthe highest frequencies andshortest wavelengths No mass and no charge Travel at the speed of light Emitted when alpha decayor beta decay occurs Gamma Rays Symbol Mass Charge Damage from Gamma Rays Nuclear Decay
Thick blocks of dense materials (i.e.:concrete or lead)are required to stopgamma rays Cause less damage to biological moleculesas they pass through living tissue. Gamma rays produce fewer ions becauseit has no electric charge Do NOW: Get out your M&Ms packetput them to the side Georgia Performance Standards
SPS3. Students will distinguish the characteristics and components of radioactivity. a. Differentiate among alpha and beta particles and gamma radiation. b. Differentiate between fission and fusion. c. Explain the process half-life as related to radioactive decay. d. Describe nuclear energy, its practical application as an alternative energy, and its potential problems. The Big Idea:Radioactive Half-LifeEssential Question: What is a daughter nucleus? Radioactive Half-Life
Half-Lifelength of time it takes of theatoms of a sample of the isotope todecay can be seconds to years The nucleus left after the isotope decaysis called the daughter nucleus. Radioactive Half-Life
The amounts of aradioactive isotopeand its daughternucleus are neededto date materials. Sample Half-Lives Isotope Half-Life 3 H 1 12.3 years 212 Pb 82 10.6 years 14C 6 5,730 years 211Po 84 0.5 s 235 U 92 7.04 X 108 years 131 I 53 8.04 days https://www.khanacademy.org/science/chemistry/radioactive-decay/v/half-life Radioactive Half-Life
Purpose: To determine the half-life of theelement M & Mium. **Radioactive members of this isotope familyare easily distinguished via a bold M on thefront surface of the atom.** Materials: Individualized size bag of M & Mium Isotopes One plastic cup Radioactive Half-Life
Procedure: 1. Count the number of M & Mium atoms asyou place them in the cup. Record the totalnumber of radioactive atoms you start with inyour data table (on the back of your graphpaper). 2. Cover and shake/rattle the cup. Radioactive Half-Life
Procedure: 3. Carefully pour your atoms onto your whitepaper. You will see that several of thepreviously radioactive atoms in the grouphave decayed, and the m is no longervisible. This means that they are nowconsidered "safe" and, since they are nolonger radioactive, may actually be eatenwithout fear of any harm to you! Radioactive Half-Life
Procedure: 3. conti: Please do so, and as you remove theedible atoms, count them so you maydetermine the number of atoms that havedecayed in that particular shake. 4. Now you need to continue this pattern untilno more radioactive members remain.Remember to record the number ofdecayed atoms after each shake! Radioactive Half-Life
Data Table: Trial (1-14) # Undecayed (Radioactive) 1 2 3 4 5 6 7 Radioactive Half-Life
Analysis: Using the graph paper provided, construct a graph by plotting the number of half lives as the independent variable (x-axis) and the number of un-decayed atoms as the dependent variable (y-axis). Remember to label you x-axis, y-axis, and indicate a title for your graph. Radioactive Half-Life
Questions: In your lab experience, you stopped when youreached zero un-decayed isotopes. Howaccurate is this when talking about half-lives? Do you think your graph would have beendifferent if you had started with more pieces ofcandy, for example 500 or 1000? Explain. Assume that each trial took 30 seconds. Based onyour results, what is the half-life of M & Mium? Radioactive Half-Life
The value for the half-life is obtained as follows: Select two values on the y-axis. One value should betwice as large as the other (i.e.: 60 & 30) Draw lines from these points to your line. Next, vertical lines should be drawn from wherethese lines intersect your lines to the x-axis. Thespace between these lines on the x-axis is the half- life. Do NOW: Discuss with your table group the difference in fusion and fission. Georgia Performance Standards
SPS3. Students will distinguish the characteristics and components of radioactivity. a. Differentiate among alpha and beta particles and gamma radiation. b. Differentiate between fission and fusion. c. Explain the process half-life as related to radioactive decay. d. Describe nuclear energy, its practical application as an alternative energy, and its potential problems. The Big Idea:Nuclear ReactionsEssential Question: Why is nuclear fusion safer for the environment than nuclear fission? Nuclear Reactions Nuclear Fission Fission means division
splitting a large nucleus into two or more smaller nuclei; energy is released how nuclear power plants operate Nuclear Reactions Nuclear Fusion
2 nuclei w/ low masses are combined to form 1 nucleus w/ larger mass Only at temps of millions of 0Ccan fusion occur happens in stars how sun operates Watch video Nuclear Reactions Chain reaction series of repeated fission reactions
caused by the release of neutrons in each reaction Nuclear Reactions Using Nuclear Reactions
Radioactive isotopes can be located by detecting the radiation they emit. Treatment of cancer Tracera radioisotope used to find or keep track of molecules in an organism examples: carbon-11, iodine-131 and sodium-24 doctors use it to monitor organ functions in agriculture to monitor uptake of nutrients and fertilizers Nuclear Reactions Radioactivity Nuclear Reactions
Advantages Disadvantages Using your textbook make a t-chart as indicated to the right. Do NOW: 3 Facts and a Fib Write 4 statements about nuclear fission and fusion. 3 should be facts

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