Electron Arrangement

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Electron Arrangement

  1. 1. Electron Arrangement<br />
  2. 2. Rutherford Model<br />While the Rutherford Model was an improvement over previous models, it still did not explain how the electrons were distributed around the nucleus.<br />What prevented the electrons from being pulled into the nucleus?<br />
  3. 3. Bohr Model<br />Niels Bohr proposed that electrons can circle the nucleus only in allowed paths, or orbits.<br />Electrons in these orbits give the atoms a fixed energy.<br />Electrons are in the lowest energy state closest to the nucleus.<br />Orbits are separated by areas where electrons can’t exist.<br />Electron energy is higher when the electron is in orbits farther from the nucleus.<br />
  4. 4. The Quantum Mechanical Model<br />Energy is quantized. It comes in chunks.<br />Quanta – the amount of energy needed to move from one energy level to another.<br />Quantum leap in energy<br />Schrödinger derives an equation that described the energy and position of the electrons in an atom.<br />
  5. 5. A mathematical solution<br />It is not like anything you can see.<br />It does have energy levels for electrons<br />Orbits are not circular<br />It can only tell us the probability of finding an electron a certain distance from the nucleus.<br />The electron is found inside a blurry “electron cloud.”<br />
  6. 6. Atomic Orbitals<br />Principal Quantum Number (n) = the energy level of the electron<br />Within each energy level the complex math of Schrödinger’s equation describes several shapes.<br />These are called atomic orbitals.<br />Regions where there is a high probability of finding an electron.<br />
  7. 7. S Orbitals<br />1 s orbital for every energy level<br />Spherical shaped<br />Each s orbital can hold 2 electrons<br />Called the 1s, 2s, 3s, etc. orbitals<br />S Orbital<br />
  8. 8. P Orbitals<br />Start at the second energy level<br />3 different directions<br />3 different shapes (dumbell)<br />Each can hold 2 electrons<br />P Orbital<br />
  9. 9. D Orbitals<br />Start with the third energy level<br />5 different shapes<br />Each can hold 2 electrons<br />D Orbital<br />
  10. 10. F Orbitals<br />Start at the 4th energy level<br />Have seven different shapes<br />2 electrons per shape<br />F Orbital<br />
  11. 11. Summary<br />
  12. 12. By Energy Level<br />1st Energy Level<br />Only s orbital<br />Only 2 electrons<br />1s2<br />2nd Energy Level<br />s & p orbitals<br />2 in s, 6 in p<br />2s22p6<br />8 total electrons<br />
  13. 13. Filling Order<br />Lowest energy fills first<br />The energy levels overlap<br />The orbitals do not fill up order of energy level<br />Counting system<br />Each “___” is an orbital shape<br />Room for 2 electrons<br />
  14. 14. 7s 7p<br />__ __ __ __<br />6s 6p 6d<br />__ __ __ __ __ __ __ __ __ <br />5s 5p 5d 5f<br />__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __<br />4s 4p 4d 4f<br />__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __<br />3s 3p 3d <br />__ __ __ __ __ __ __ __ __<br />2s 2p<br />__ __ __ __<br />1s<br />__<br />Increasing Energy<br />
  15. 15. Electron Configurations<br />The way electrons are arranged in atoms<br />Aufbau principle – electrons enter the lowest energy level first<br />This causes difficulties because of the overall of orbitals of different energies<br />Paulie Exclusion Principle – at most 2 electrons per orbital – different spins<br />Hund’s Rule – when electrons occupy orbital of equal energy, they don’t pair up until they have to<br />
  16. 16. Practice<br />Phosphorus<br />How many electrons??<br />Account for 15<br />
  17. 17. 7f __ __ __ __ __ __ __<br /> 7d __ __ __ __ __<br /> 6f __ __ __ __ __ __ __<br /> 7p __ __ __<br /> 6d __ __ __ __ __<br /> 5f __ __ __ __ __ __ __<br />7s __<br /> 6p __ __ __<br /> 5d __ __ __ __ __<br /> 4f __ __ __ __ __ __ __<br />6s __<br /> 5p __ __ __<br /> 4d __ __ __ __ __<br />5s __<br /> 4p __ __ __<br /> 3d __ __ __ __ __<br />4s __<br /> 3p __ __ __<br />3s __<br /> 2p __ __ __<br />2s __<br />1s __<br />Filling Order<br />
  18. 18. Orbital Notation for Phosphorous<br />
  19. 19. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s2<br />2 electrons<br />
  20. 20. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s2<br />4 electrons<br />
  21. 21. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s2<br />12 electrons<br />
  22. 22. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s23p64s2<br />20 electrons<br />
  23. 23. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s23p64s23d104p65s2<br />38 electrons<br />
  24. 24. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s23p64s23d104p65s24d105p66s2<br />56 electrons<br />
  25. 25. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s23p64s23d104p65s24d105p66s24f14<br /> 5d106p67s2<br />88 electrons<br />
  26. 26. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s23p64s23d104p65s24d105p66s24f14<br /> 5d106p67s25f146d107p6<br />118 electrons<br />
  27. 27. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s23p64s23d104p65s24d105p66s24f14<br /> 5d106p67s25f146d107p66f147d10<br />142 electrons<br />
  28. 28. A trick…<br />7s 7p 7d 7f<br />6s 6p 6d 6f<br />5s 5p 5d 5f<br />4s 4p 4d 4f<br />3s 3p 3d<br />2s 2p<br />1s<br />1s22s22p63s23p64s23d104p6<br />5s24d105p66s24f145d106p67s25f146d107p66f147d107f14<br />156 electrons<br />Aufbau Principle<br />
  29. 29. Rewrite when done..<br />1s22s22p63s23p64s23d104p65s24d105p66s2<br /> 4f145d106p67s25f146d107p66f147d107f14<br />Group the energy levels together<br />1s22s22p63s23p63d104s24p64d104f145s25p65d105f146s26p66d106f147s27p67d107f14<br />
  30. 30. Exceptions to Electron Configurations<br />
  31. 31. Orbitals fill in order…<br />Lowest energy to higher energy<br />Adding electrons can change the energy of the orbital<br />Filled and half-filled orbitals have a lower energy<br />Makes them more stable<br />Changes the filling order of d orbitals<br />
  32. 32. Practice<br />Vanadium<br />1s22s22p63s23p63d34s2<br />Titanium<br />1s22s22p63s23p63d24s2<br />Chromium<br />(expected)1s22s22p63s23p63d44s2<br />(correct) 1s22s22p63s23p63d54s1<br />Why? It more stable – gives us two half-filled orbitals!<br />
  33. 33. Exceptions<br />Same principle applies to Copper!<br />Remember these exceptions:<br />d4s2 d5s1<br />d9s2  d10s1<br />
  34. 34. Electrons on the Periodic Table<br />
  35. 35. Table 3(p. 116)<br />Notice that as you move across the periodic table, the elements increase in the number of electrons.<br />Notice the electron-configuration notation  Aufbau Principle<br />
  36. 36. Noble Gas Notation<br />The elements all the way to the right of the periodic table make up Group 18.<br />Their sublevels are completely filled, and they are said to have an octet of electrons.<br />These elements (helium, neon, argon, krypton, xenon, and radon) are called Noble Gases.<br />We can use their electron configurations to simplify the electron configurations we write for other elements!<br />
  37. 37. Example<br />Neon<br />Ne = 1s22s22p6<br />Sodium<br />Na = [Ne]3s1<br />Tables 4 - 6 (pp. 117-120)<br />Noble-Gas Configuration<br />Refers to an outer main energy level occupied, in most cases, by eight electrons.<br />

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