Lecture 25.1- Radiation


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Section 25.1 Lecture for Honors and Prep Chemistry

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  • Lecture 25.1- Radiation

    1. 1. Bellwork- atomic structure Fill in the chart Subatomic particle Location (in or out of nucleus) Charge Mass Proton Neutron Electron
    2. 2. Lecture 25.1- Nuclear Radiation <ul><li>Marie Curie was a Polish scientist whose research led to many discoveries about radiation and radioactive elements. In 1934 she died from leukemia caused by her long-term exposure to radiation. You will learn about the various types of radiation and their effects. </li></ul>25.1
    3. 3. <ul><ul><ul><li>Marie Curie (1867-1934) and Pierre Curie (1859-1906) were able to show that rays emitted by uranium atoms caused fogging in photographic plates. </li></ul></ul></ul><ul><ul><ul><ul><li>Marie Curie named the process by which materials give off such rays radioactivity . </li></ul></ul></ul></ul><ul><ul><ul><ul><li>The penetrating rays and particles emitted by a radioactive source are called radiation . </li></ul></ul></ul></ul>25.1
    4. 4. <ul><ul><ul><li>Nuclear reactions differ from chemical reactions in a number of important ways. </li></ul></ul></ul><ul><ul><ul><ul><li>In chemical reactions, atoms tend to attain stable electron configurations by losing or sharing electrons. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>In nuclear reactions, the nucleus gains stability by undergoing changes. </li></ul></ul></ul></ul>25.1
    5. 5. <ul><ul><li>An unstable nucleus releases energy by emitting radiation during the process of radioactive decay . </li></ul></ul><ul><li>An unstable nucleus is called a radioisotope . </li></ul>
    6. 6. <ul><ul><ul><li>The three main types of nuclear radiation are alpha radiation, beta radiation, and gamma radiation. </li></ul></ul></ul>25.1
    7. 7. <ul><ul><li>Alpha radiation consists of helium nuclei. </li></ul></ul><ul><ul><ul><li>These particles, called alpha particles, contain two protons and two neutrons and have a double positive charge. </li></ul></ul></ul>25.1
    8. 8. <ul><ul><ul><li>An electron resulting from the breaking apart of a neutron in an atom is called a beta particle . </li></ul></ul></ul>25.1
    9. 9. <ul><li>Carbon-14 emits a beta particle as it undergoes radioactive decay to form nitrogen-14. </li></ul>25.1
    10. 10. 25.1
    11. 11. 25.1
    12. 12. <ul><ul><ul><li>A high-energy photon emitted by a radioisotope is called a gamma ray . </li></ul></ul></ul><ul><ul><ul><li>Gamma rays are electromagnetic radiation. </li></ul></ul></ul><ul><ul><li>Gamma ray emission does not change the element. </li></ul></ul>25.1
    13. 13. <ul><ul><ul><li>Alpha particles are the least penetrating. </li></ul></ul></ul><ul><ul><ul><li>Gamma rays are the most penetrating. </li></ul></ul></ul>25.1
    14. 14. particle Alpha  Beta  Gamma  Mass 4amu ≈ 0 0 Charge +2 -1 0 Effect on nucleus loses two protons and two neutrons The ELEMENT changes converts a neutron to a proton & ejects an electron The ELEMENT changes loses energy The element does not change What it is Helium nucleus electron High energy electromagnetic radiation Stop it Paper/skin 1cm/metal foil Lead/concrete damage High ionization Medium ionization Lowest ionization
    15. 15. <ul><ul><li>1. Certain elements are radioactive because their atoms have </li></ul></ul><ul><ul><ul><li>more neutrons than electrons. </li></ul></ul></ul><ul><ul><ul><li>an unstable nucleus. </li></ul></ul></ul><ul><ul><ul><li>a large nucleus. </li></ul></ul></ul><ul><ul><ul><li>more neutrons than protons. </li></ul></ul></ul>25.1 Section Quiz.
    16. 16. <ul><ul><li>2. An unstable nucleus releases energy by </li></ul></ul><ul><ul><ul><li>emitting radiation. </li></ul></ul></ul><ul><ul><ul><li>thermal vibrations. </li></ul></ul></ul><ul><ul><ul><li>a chemical reaction. </li></ul></ul></ul><ul><ul><ul><li>giving off heat. </li></ul></ul></ul>25.1 Section Quiz.
    17. 17. <ul><ul><li>3. Which property does NOT describe an alpha particle? </li></ul></ul><ul><ul><ul><li>2+ charge </li></ul></ul></ul><ul><ul><ul><li>a relatively large mass </li></ul></ul></ul><ul><ul><ul><li>a negative charge </li></ul></ul></ul><ul><ul><ul><li>low penetrating power </li></ul></ul></ul>25.1 Section Quiz.
    18. 18. <ul><ul><li>4. When a radioactive nucleus releases a high-speed electron, the process can be described as </li></ul></ul><ul><ul><ul><li>oxidation. </li></ul></ul></ul><ul><ul><ul><li>alpha emission. </li></ul></ul></ul><ul><ul><ul><li>beta emission. </li></ul></ul></ul><ul><ul><ul><li>gamma radiation. </li></ul></ul></ul>25.1 Section Quiz.