2 StandardsSPS3. Students will distinguish the characteristics and components of radioactivitySPS3a. Differentiate among alpha and beta particles and gamma radiation.SPS3b. Differentiate between fission and fusion.SPS3c. Explain the process half-life as related to radioactive decay.SPS3d. Describe nuclear energy, its practical application as an alternative energy source, and its potential problems.
3 Nuclear Radiation Radioactive Decay: unstable isotopes emit particles and release energy to become stableisotopes.after radioactive decay, the element changes into a different isotope of the same element or into an entirely different element.
4 RadiationNuclear Radiation: particles and energy released from the nucleus during radioactive decay.
5 Types of Radiation 2+ 1- Alpha () -protons and neutrons paperBeta-minus (-)-electrons and positrons1-leadGamma ()-high-energy photonsconcrete
6 Types of Nuclear Radiation (pg 238) Radiation TypeSymbolWhat is it?Mass (kg)ChargeTravel depth through materialsAlpha particle2 protons and 2 neutrons6.646x10-27+2Least far due to massive sizeBeta particleFast-moving electrons or positrons9.109x10-31-1, (+1)Farther than alpha, but still not farGamma rayForm of electromagnetic energyNoneThrough clothes; Can cause harmNeutronA neutron leaving the nucleus1.675x10-27Penetrate the farthest
7 Nuclear DecayAnytime an unstable nucleus emits alpha or beta particles, the number of protons and neutrons changes.Alpha decay: atomic mass and number changeBeta decay: atomic number changesGamma decay: energy of the nucleus is lower, but no change in atomic number or mass
8 Nuclear Decay Why nuclide (nucleus of an isotope) decay… to obtain a stable ratio of neutrons to protonsStableUnstable(radioactive)
9 + Ra He Rn 226 = 222 + 4 88 = 86 + 2 Alpha Decay (atomic mass & atomic number change)
10 (atomic mass stays the same; atomic number changes by 1) Beta Decay Equations146+Ce-1714 =6 = 7 + (-1)(atomic mass stays the same; atomic number changes by 1)
11 Actinium-217 decays by releasing an alpha particle Actinium-217 decays by releasing an alpha particle. Write the equation for this decay process and determine which element is formed.22789+Ac4He2AZX
12 Complete the following radioactive-decay equation Complete the following radioactive-decay equation. Identify the isotope X. Indicate whether alpha or beta decay takes place.6328+Nie-1AZX
13 Radioactive Decay Rates Half-life: time in which half of a radioactive substance decays; measure of how quickly a substance decays.-Iodine-131: used by doctors to diagnose medical problems-Potassium-40: used by geologists to predict the age of rocks
14 Calculating Half-Life Radium-226 has a half-life of 1599 years. How long will 7/8 of a sample take to decay?Find out how much will be left.8/8 - 7/8 = 1/8 left over2. Calculate how many half-lives until only 1/8 is left.11/21/41/8One half lifeTwo half livesThree half lives3. Calculate how many years it will take for 3 half lives to occur.1599 x 3 = 4797 years
15 Nuclear FissionNuclear fission: the process by which a nucleus splits and neutrons and energy are released.Nuclear chain reaction: a continuous series of fission reactions (pg 340)
16 Nuclear FusionNuclear fusion: when 2 light nuclei combine to form a heavier nuclei-Hydrogen is turned into Helium on the sun.(pg 342)
17 Radiation on Earth All around you. Background radiation: arises naturally from the sun, soil, rocks, and plantsYou are exposed to more radiation in the mountains than at sea level
18 Beneficial Uses of Radiation Smoke detectors release alpha particlesRadiation is used in x rays, MRIs, CT scans, PET scans, and ultrasoundsRadiation therapy is used to treat cancerUsed in agriculture to track the flow of water
19 Nuclear Radiation Risks High levels of radiation exposure can cause radiation sicknessHigh concentrations of radon gas can cause cancer
20 Nuclear Power Advantages Disadvantages Does not produce greenhouse gasesRadioactive products must be handled and stored carefully so they do not escape.Much more energy available in uranium reserves than gas and coal.Expensive to build due to many safety regulations.Waste must be stored in areas away from people, homes, water, earthquakes.