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Drill – 10/21 PowerPoint Presentation
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Drill – 10/21

Drill – 10/21

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Drill – 10/21

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  1. Drill – 10/21 • Clear desk of everything and take outline, ½ sheet of paper, and pen or pencil out

  2. Pop Reading Quiz • What is the energy released when a nucleus is formed from nucleons called? • The band of stability shows that at low atomic numbers the most stable elements are those with what neutron to proton ratio? • Give an example of a nuclear equation • Give the 5 types of radioactive decay • What is half-life?

  3. Objective • SWBAT explain how some isotopes are made of unstable nuclei that decay over time emitting particles and energy. • SWBAT contrast alpha, beta, & gamma emissions, the composition of each, and the material required to shield them. • SWBAT balance a nuclear equation.

  4. Alpha, Beta, & Gamma Radiation • Measured by passing radiation through electrically charged plates.

  5. Alpha Radiation α • Deflected towards the negative plate…so POSITIVE. • Alpha particles are a Helium nucleus – with 2 protons and 2 neutrons 4 He 2

  6. Alpha Radiation α 238 234 4 U Th + He 92 90 2 Uranium-238 Thorium-234 Alpha Particle Note that the mass number always decreases by 4 after the alpha emission. Atomic number decreases by 2

  7. Beta Radiation β • Deflected towards the positive plate…so NEGATIVE • Beta particles are fast-moving negatively charged electrons 0 β -1

  8. Beta Radiation β • How is it possible to lose an electron from the nucleus? Neutrons are theorized to be made up of a proton and an electron. 1 1 0 n H + e 0 1 -1 A neutron is changed into a proton and an electron and the electron is emitted.

  9. Beta Radiation β 234 279 0 Th Pa + e 90 91 -1 Thorium-234Beta particle By combining the charges from the bottom of the two symbols, figure out the symbol for the remaining particle ?

  10. Beta Radiation β 234 234 0 Th Pa + e 90 91 -1 Thorium-234Beta particle By combining the charges from the bottom of the two symbols, figure out the symbol for the remaining particle Pa Protactinium-234

  11. Gamma Radiation γ • Not deflected by charged plates…so NO CHARGE • Gamma rays are high-energy electromagnetic radiation (like u-v or radio or x-rays) with no mass • They have very SHORT wavelength • They have HIGH energy 0 γ 0

  12. http://www.whfreeman.com/chemcom/content.htm#

  13. 10/22 • How many milligrams of a 15.0 mg sample of radium-226 remain after 6300 years? The half-life of radium-226 is 1599 years.

  14. 10/22 • The half-life for radium-224 is 3.66 days. What was the original mass of radium-224 if 0.0500g remain after 7.76 days?