Atomic Structure


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Atomic Structure

  1. 1. Atomic Theory Atomic Structure Chapter 2 Atoms
  2. 2. Discovering the Elements <ul><li>Elements are the building blocks of all matter </li></ul>
  3. 3. Elements Intro
  4. 4. Atomic Theory <ul><li>“If I have seen further, it is by standing on the shoulders of giants.” Isaac Newton </li></ul><ul><li>What does this mean to you? </li></ul>
  5. 5. Greek Philosopher’s contribution
  6. 6. Greek Philosophers <ul><li>Aristotle </li></ul><ul><ul><li>4 Elements of matter </li></ul></ul><ul><li>Democritus </li></ul><ul><li>matter is made of atoms (cannot be further divided) </li></ul>Earth Fire Air Water
  7. 8. Modern Theory <ul><li>Alchemist believed that all matter was made of a limited number of elements. </li></ul><ul><li>Elements are basic substances that cannot be broken down into simpler forms by ordinary means. </li></ul><ul><li>92 exist in nature - </li></ul><ul><li>20 synthetic - </li></ul>
  8. 10. <ul><li>Atoms were tiny particles that could not be divided </li></ul><ul><li>Each element had its own kind of atom </li></ul><ul><li>John Dalton proposed that an atom is a sphere of matter that is the same throughout. </li></ul><ul><li>Marble Model </li></ul>John Dalton
  9. 12. <ul><li>Came up with the idea of the electron – negatively charged particle </li></ul><ul><li>J.J. Thomson discovered that all atoms contain electrons, which are tiny, negatively charged particles. Thomson proposed that an atom is a sphere of positive charge. The electrons are mixed uniformly in the sphere. </li></ul><ul><li>Clay with embedded </li></ul><ul><li>spheres </li></ul>JJ Thomson
  10. 14. Ernest Rutherford <ul><li>He hypothesized that almost all the mass and all the positive charge of an atom is concentrated in an extremely tiny nucleus at the center of the atom. </li></ul>
  11. 16. <ul><li>Thought electrons traveled in fixed paths around the nucleus called energy levels. </li></ul>Niels Bohr
  12. 17. <ul><li>Electrons are in random orbits around the nucleus </li></ul><ul><li>Electrons move rapidly throughout the atom </li></ul><ul><li>Energy Levels Still Exist </li></ul>Electron Cloud
  13. 18. Electrons in Energy Levels 2 e - 8 e - 18 e - 32 e -
  14. 20. Atomic Structure <ul><li>Arrangement and number of sub-atomic particles </li></ul><ul><ul><li>Protons </li></ul></ul><ul><ul><li>Neutrons </li></ul></ul><ul><ul><li>Electrons </li></ul></ul>
  15. 22. <ul><li>Center or core of an atom </li></ul><ul><li>Contains 99.9% of the weight of an atom </li></ul><ul><li>Contains protons and neutrons </li></ul><ul><li>Occupies 1 / 100,000 of the space of an atom </li></ul>Nucleus
  16. 23. Protons <ul><li>Positively Charged Sub-atomic particles </li></ul><ul><li>Found in the nucleus </li></ul><ul><li>All protons are a like </li></ul><ul><li>Weight of 1 proton = </li></ul><ul><li>1 atomic mass unit </li></ul>
  17. 25. <ul><li>Neutrally charged (no charge) sub-atomic particle </li></ul><ul><li>Atomic weight of 1 atomic mass unit </li></ul><ul><li>Found in nucleus </li></ul>Neutron
  18. 26. <ul><li>The Number of Protons in the nucleus. </li></ul>What makes atoms different?
  19. 28. <ul><li>Atomic number is the number of Protons in an atom </li></ul><ul><li>All atoms of a particular element have the SAME number of protons (All Carbon atoms have 6 protons) </li></ul><ul><li>In a neutral atom, the atomic number = the number of electrons </li></ul>Atomic Number
  20. 29. What is a neutral atom? <ul><li>Neutral atoms have no overall charge </li></ul><ul><li># of Protons = # of Electrons </li></ul>
  21. 30. How Many Electrons? <ul><li>Copper (Cu) has an atomic number of 29. </li></ul><ul><li>How many electrons does it have? </li></ul>29
  22. 32. <ul><li>Also called atomic weight or Mass Number </li></ul><ul><li>Sum weight of protons and neutrons in an atom </li></ul>Atomic Mass
  23. 33. Periodic Table Atomic Number Element Symbol Mass Number 29 Cu 63.546
  24. 34. Calculating Neutrons <ul><li>Mass number = protons + neutrons </li></ul><ul><li>so….. </li></ul><ul><li>Neutrons = mass number – protons </li></ul>How many neutrons does Copper have? 35 Mass # = 63.546 (rounds to 64) Neutrons = 64-29 =
  25. 36. <ul><li>Atoms of the same element with different numbers of neutrons. </li></ul>Isotopes Carbon 12 Carbon 13 Carbon 14
  26. 38. <ul><li>Negatively charged sub-atomic particle </li></ul><ul><li>Weight = 0.0006 atomic mass unit </li></ul><ul><li>Move rapidly </li></ul><ul><li>Form an electron cloud (area where electrons are likely to be) </li></ul>Electron
  27. 39. <ul><li>Charged ATOMS </li></ul><ul><li># of protons does not equal # of electrons </li></ul><ul><li>Positive Ion --- cation </li></ul><ul><ul><li>More protons than electrons </li></ul></ul><ul><li>Negative Ion --- anion </li></ul><ul><ul><li>More electrons than protons </li></ul></ul>Ions
  28. 40. Number of elements <ul><li>Oddly enough, the exact number of naturally-occurring elements is uncertain. Uranium (atomic number=92) is the element with the highest atomic number found in significant quantities on earth or elsewhere . The elements astatine (atomic number=85) and francium (atomic number=87), along with all the other known elements (up to atomic number 109) were discovered when first made artificially; if they occur naturally, then they exist only in exceedingly small amounts. </li></ul>
  29. 41. Bibliography <ul><li>Discovering the Elements. United Learning (1996). Retrieved October 12, 2006, from unitedstreaming: </li></ul><ul><li>Physical Science Series: Atomic Structure and the Periodic Table. United Learning (1998). Retrieved October 12, 2006, from unitedstreaming: </li></ul>