9th Grade Chapter 5 Lesson 2


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9th Grade Chapter 5 Lesson 2

  1. 1. 9 th Grade Chapter 5 Lesson 2 Pgs. 120-131 For Student Use Only
  2. 2. Inside the Atom <ul><li>Atoms are made up of small particles called sub-atomic particles </li></ul><ul><ul><li>Subatomic Particles </li></ul></ul><ul><ul><ul><li>Found in Nucleus: </li></ul></ul></ul><ul><ul><ul><ul><li>Neutrons- carry no charge </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Protons- carry a positive charge </li></ul></ul></ul></ul><ul><ul><ul><li>Atomic Number= number of protons in an element </li></ul></ul></ul><ul><ul><ul><li>Isotope= atoms with different numbers of neutrons </li></ul></ul></ul>
  3. 3. Inside the Atom <ul><li>Subatomic Particles: </li></ul><ul><ul><li>Quarks- make up protons and neutrons </li></ul></ul><ul><ul><ul><li>These were not known for a long time </li></ul></ul></ul><ul><ul><ul><li>There are 2 types of quarks: </li></ul></ul></ul><ul><ul><ul><ul><li>Up quarks- has a 2/3 positive charge </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Down quarks- has a 1/3 negative charge </li></ul></ul></ul></ul><ul><ul><ul><ul><li>It takes 3 quarks to make up a neutron or proton </li></ul></ul></ul></ul>
  4. 4. Inside the Atom <ul><li>There is another component of the atom </li></ul><ul><ul><li>Electrons- negatively charges particles </li></ul></ul><ul><ul><ul><li>Electrons do not seem to make up anything else </li></ul></ul></ul><ul><ul><li>Electrons are arranged in an electron shell. </li></ul></ul><ul><ul><li>Energy levels divide the electron shells </li></ul></ul>
  5. 5. Inside the Atom <ul><li>Electron Shells </li></ul><ul><ul><li>Electrons- energy levels hold more electrons and energy as they go farther away </li></ul></ul><ul><ul><li>When atoms have a charge: </li></ul></ul><ul><ul><ul><li>Ions: an atom that lost or gained electrons </li></ul></ul></ul><ul><ul><ul><li>Anions: negative ions </li></ul></ul></ul><ul><ul><ul><li>Cations: positive ions </li></ul></ul></ul>
  6. 6. Inside the Atom <ul><li>Atoms- </li></ul><ul><ul><li>Neutrinos- little neutral one </li></ul></ul><ul><ul><ul><li>No electric charge and little mass </li></ul></ul></ul><ul><li>Atomic Models: </li></ul><ul><ul><li>Illustrate the internal structure of the atom </li></ul></ul><ul><ul><li>The atoms originally were drawn like hard spheres </li></ul></ul>
  7. 7. Inside the Atom <ul><li>Quantum Theory: </li></ul><ul><ul><li>States that tiny particles such as electrons do not absorb or release energy in a smooth energy flow </li></ul></ul><ul><ul><li>Quantum: Energy is always absorbed or released in a discrete packet called a quantum </li></ul></ul><ul><ul><li>Electrons change shells or orbits as they gain or lose electrons. </li></ul></ul>
  8. 8. Inside the Atom <ul><li>Bohr Model: </li></ul><ul><ul><li>Most famous model of an atom </li></ul></ul><ul><li>Wave-Mechanical Model: </li></ul><ul><ul><li>Electrons have the same structure of both waves and particles </li></ul></ul><ul><li>Heisenberg Uncertainty Principle: </li></ul><ul><ul><li>Explains where a certain electron will be at a certain place </li></ul></ul>
  9. 9. Inside the Atom <ul><li>Electron Cloud Model (aka- quantum mechanical model)- </li></ul><ul><ul><li>Electrons do not have particular orbits, they are in a regions called orbitals </li></ul></ul><ul><li>Atomic Measurement </li></ul><ul><ul><li>Mass of Atom- this is the amount of “stuff” in an atom </li></ul></ul><ul><ul><li>Mass Number- number of protons and neutrons in an atom’s nucleus. </li></ul></ul>
  10. 10. Inside the Atom <ul><li>Mass Number Notes: </li></ul><ul><ul><li>Always whole numbers </li></ul></ul><ul><ul><li>Represent whole particles </li></ul></ul><ul><ul><li>More mass= higher mass number </li></ul></ul><ul><ul><li>Creates Isotopes- isotopes have same number of protons, but different number of neutrons and leads to different mass numbers </li></ul></ul>
  11. 11. Inside the Atom <ul><li>Average Mass Number- </li></ul><ul><ul><li>The isotopes (that exist naturally) are averaged together and relative to the percentage found in nature </li></ul></ul><ul><ul><li>It measures Atomic Mass Unit. </li></ul></ul><ul><ul><ul><li>AMU= 1/12 the mass of a carbon-12 atom </li></ul></ul></ul>
  12. 12. Inside the Atom <ul><li>Atomic Mass: </li></ul><ul><ul><li>The average of all the isotopes of an element </li></ul></ul><ul><ul><li>This is what chemists use when they say atomic mass </li></ul></ul><ul><ul><li>This is also called the mass number </li></ul></ul>
  13. 13. Inside the Atom <ul><li>Nuclear Decay: </li></ul><ul><ul><li>Isotopes of certain atoms give off radiation </li></ul></ul><ul><ul><li>Most atoms nuclei are stable, BUT some are not, the unstable atoms give off radiation </li></ul></ul><ul><ul><li>Unstable= an atom that is capable of changing into another atom </li></ul></ul><ul><ul><li>This unstable substance is called radioactive! </li></ul></ul>
  14. 14. Inside the Atom <ul><li>Decay Rate: </li></ul><ul><ul><li>Half-life= the rate at which an atom breaks down </li></ul></ul><ul><ul><li>There are 2 main types of Radioactive Decay + Gamma: </li></ul></ul><ul><ul><ul><li>Alpha Decay- made up of 2 neutrons and 2 protons that are released from the center of the atom </li></ul></ul></ul><ul><ul><ul><li>Beta Decay- when a neutron changes into a proton and an electron is ejected from the atom </li></ul></ul></ul><ul><ul><ul><li>Gamma Radiation- not part of radioactive decay- usually occurs after alpha or beta radiation </li></ul></ul></ul>
  15. 15. Inside the Atom <ul><li>Radiation: </li></ul><ul><ul><li>All types of radiation can affect human beings (in large amounts) </li></ul></ul><ul><ul><ul><li>Alpha Particles: </li></ul></ul></ul><ul><ul><ul><ul><li>Less dangerous- not as much energy </li></ul></ul></ul></ul><ul><ul><ul><li>Beta particles: </li></ul></ul></ul><ul><ul><ul><ul><li>More energy, more dangerous </li></ul></ul></ul></ul><ul><ul><ul><li>Gamma Radiation: </li></ul></ul></ul><ul><ul><ul><ul><li>Most powerful, most dangerous </li></ul></ul></ul></ul>
  16. 16. Inside the Atom <ul><li>Radiation: </li></ul><ul><ul><li>We are constantly opposed to radiation that occurs naturally </li></ul></ul><ul><ul><li>Our bodies naturally fix themselves </li></ul></ul><ul><ul><li>Above a certain amount of radiation cancer and other health problems may occur, </li></ul></ul><ul><ul><li>Below a certain level of radiation there is no harm done </li></ul></ul>
  17. 17. Inside the Atom <ul><li>Radiation can be useful </li></ul><ul><ul><li>How is radiation useful? </li></ul></ul><ul><li>Nuclear Radiation: </li></ul><ul><ul><li>Nuclear Fission: </li></ul></ul><ul><ul><ul><li>In 1930’s discovered that by bombarding nucleus with neutrons they can split the nucleus </li></ul></ul></ul>
  18. 18. Inside the Atom <ul><li>Nuclear Fission: </li></ul><ul><ul><li>The splitting of an nucleus releases large amounts of energy </li></ul></ul><ul><ul><ul><li>Scientists discovered that by bombarding a nucleus with neutrons it will divide </li></ul></ul></ul><ul><ul><li>Nuclear Fission- when a nucleus splits </li></ul></ul><ul><ul><li>Chain Reaction- The nucleus splits and the neutrons hit other nucleuses and causes them to split </li></ul></ul>
  19. 19. Inside the Atom <ul><li>Nuclear Fission: </li></ul><ul><ul><li>Critical Mass- there must be a certain amount of fissionable material to create a chain reaction </li></ul></ul><ul><ul><ul><li>Uncontrolled Fission- in an atomic bomb </li></ul></ul></ul><ul><ul><ul><li>Controlled Fission- in a nuclear reactor it creates useful energy </li></ul></ul></ul><ul><ul><ul><li>Breeder Reactors- produce more nuclear fuel than they use </li></ul></ul></ul>
  20. 20. Inside the Atom <ul><li>Nuclear Fission: </li></ul><ul><ul><li>Chernobyl- a site if a big accident caused by a series of mistakes </li></ul></ul><ul><li>Nuclear Fusion: </li></ul><ul><ul><li>The joining of nucleuses releases large amounts of energy </li></ul></ul><ul><ul><li>Sun is powered by fusion </li></ul></ul><ul><ul><li>Fusion is harder to produce than fission </li></ul></ul><ul><ul><li>Hydrogen Bomb is nuclear fusion </li></ul></ul>