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Radioactivity & Nuclear Rxns Chapter 6.1 & 6.2. Nuclear Radiation  Comes from an unstable nucleus  Radiation can be released as either… –Particles –or.

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Presentation on theme: "Radioactivity & Nuclear Rxns Chapter 6.1 & 6.2. Nuclear Radiation  Comes from an unstable nucleus  Radiation can be released as either… –Particles –or."— Presentation transcript:

1 Radioactivity & Nuclear Rxns Chapter 6.1 & 6.2

2 Nuclear Radiation  Comes from an unstable nucleus  Radiation can be released as either… –Particles –or Energy (such as electromagnetic radiation) –or Both

3 Types of Radiation  Ionizing Radiation causes atoms to become charged (ions) –Alpha & Beta Particles –Neutron Emission –High Freq. Electromagnetic Radiation (x-rays)  Nonionizing Radiation –Visible Light –Infrared –Microwaves and Radio waves

4 Nuclear Decay When an unstable nucleus emits an alpha or beta particle… …the number of protons or neutrons changes. This means that the identity and/or the mass of the atom will change also.

5 Radioactive Decay Rates  Decay is spontaneous and random… –when observing ONE atom.  When observing a large sample of material the decay is no longer random.

6 Radioactive Decay Rates  Half-life –This is the time required for half of a sample to decay.  Examples –Uranium-238  4.47 x 10 9 years –Potassium-40  1.28 x 10 9 years –Carbon-14  5730 years –Iodine-131  8.1 days –Hafnium-156  seconds

7 Review of the Nucleus  Contents –Protons –Neutrons  Active Forces –Repulsions –Strong Nuclear Force

8 Nuclear FISSION  Splitting a nucleus into smaller fragments.  This also releases neutrons and energy.

9 Nuclear Fission (con’t)

10  Hahn and Strassman conducted experiments on fission in 1939  They found the mass before and after the reaction was not equal. –Where did the mass go? –Remember the Laws of Conservation?  Mass and Energy were found to be equivalent!!!

11 There is an equation for this… IT’S WRITTEN AS… E = mc 2 c = speed of light

12 Nuclear Fission (con’t) How much energy is converted from mass? 5 lb. of mass, converted all into energy is equal to 16 million TONS of TNT Fortunately, most objects are stable and never spontaneously change into energy!

13 Nuclear FUSION  Combining two light nuclei into a heavier nuclei  This also releases energy. This process takes place naturally in stars. It’s how our elements were formed. Scientists are trying to make it work in a lab.

14 Nuclear Fusion (con’t)

15 Animations Fission Fusion


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