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ELECTRONS AND THEIR LOCATION

ELECTRONS AND THEIR LOCATION. ELECTRON ADDRESSES. RULES TO REMEMBER. HEISENBERG UNCERTAINTY PRINCIPLE –Cannot know the exact location of an electron. Fundamentally impossible to know both the location and momentum/velocity of an electron at the same time.

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ELECTRONS AND THEIR LOCATION

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  1. ELECTRONS AND THEIR LOCATION ELECTRON ADDRESSES

  2. RULES TO REMEMBER • HEISENBERG UNCERTAINTY PRINCIPLE –Cannot know the exact location of an electron. Fundamentally impossible to know both the location and momentum/velocity of an electron at the same time. • The quantum mechanical model merely suggests the probability of the electron location. • No circular orbits – Sorry Bohr!

  3. Aufbau Principle • Electrons fill the lowest possible energy level. • Energy levels correspond to period number on the Periodic Table. • How many energy levels are there?

  4. Pauli Exclusion Principle • No more than two (2) electrons in an orbital.

  5. Hund’s Rule(s) • 1) Orbitals of equal energy must fill singly before doubling. That means each must have one electron before any of that same level can have two electrons. • 2. All electrons in singly occupied orbitals have the same spin direction • 3. Pairs of electrons in the same orbital have opposite spin.

  6. QUANTUM NUMBERS • Describe the electron’s “address” • 1st Quantum is the principle quantum – describes the energy level. (1,2,3, etc.) • 2nd Quantum describes the shape of the orbitals. s,p,d,f • 3rd Quantum describes the orientation of the orbital • 4th Quantum describes the spin of the electron • we will use only the 1st & 2nd quantum numbers

  7. http://player.discoveryeducation.com/index.cfm?guidAssetId=163B32D5-42B7-402B-9AB6-C48679F58C9E&blnFromSearch=1&productcode=UShttp://player.discoveryeducation.com/index.cfm?guidAssetId=163B32D5-42B7-402B-9AB6-C48679F58C9E&blnFromSearch=1&productcode=US

  8. Shapes of orbitals • s on page 371 • p on page 372 • d on page 374

  9. What do you think the 5th energy level looks like? • The pattern stops – it looks like the 4th energy level • What about 6 & 7?

  10. Electron Configurations: Here we go now!! • Hydrogen is in the first period, therefore has only one energy level. The first energy level has only one orbital – the s orbital. Hydrogen has only 1 electron so, its electron configuration is • 1s1

  11. Helium is also in the first period, therefore has only one energy level. The first energy level has only one orbital – the s orbital. Helium has 2 electrons so, its electron configuration is • 1s2

  12. Lithium is in the second period, therefore has two energy levels. The first energy level has only one orbital – the s orbital. The second energy level has both s and p orbitals – one s and three p orbitals. Lithium has 3 electrons so, its electron configuration is • 1s22s1 Notice that the superscripts add up to the number of electrons.

  13. Let’s try beryllium • 2nd period with 4 electrons • 1s22s2 • Now boron - again, notice that the superscripts add up to the atomic number which is equal to the number of electrons • 1s22s22p1 • Carbon • 1s22s22p2

  14. Quick Quiz • A. How many electrons can the p orbitals hold if filled? • B. How many kinds of orbitals are in the 4th energy level? • C. What are the orbitals of the 2nd energy level? • D. How many f orbitals are there? • E. How many electrons can any one orbital hold? • F. At most, how many electrons in the 2nd energy level?

  15. That’s all for today!!

  16. Orbital Diagrams or Orbital Configurations • Use boxes and arrows to represent electrons in various energy levels. • Boxes must be labeled with regard to energy level and orbitals.

  17. H orbital configuration 1s

  18. H He orbital configuration 1s 1s

  19. H He Li orbital configuration 1s 1s 2s 1s

  20. H He Li Be orbital configuration 1s 1s 2s 1s 1s 2s

  21. B C orbital configuration 1s 2s 2p 1s 2s 2p

  22. N orbital configuration 1s 2s 2p

  23. Lewis Dot Structures • Element symbol represents atom nucleus and inner electrons. • Dots around the symbol represent valence (outermost energy level) electrons.

  24. Lewis dot structure 1 Symbol

  25. Lewis dot structure 1 2 Symbol

  26. Lewis dot structure 1 2 3 Symbol

  27. Lewis dot structure 1 2 3 Symbol 4

  28. Lewis dot structure 1 2 3 5 Symbol 4

  29. Lewis dot structure 1 2 5 3 Symbol 6 4

  30. Lewis dot structure 1 2 5 3 Symbol 6 4 7

  31. Lewis dot structure 1 2 3 5 Symbol 6 8 4 7

  32. Bohr Models • Use concentric circles to represent energy levels and the number of electrons in each.

  33. Bohr model H 1-

  34. Bohr model Li 2- 1-

  35. Bohr model Ne 2- 8-

  36. Bohr model S 2- 8- 6-

  37. Bohr model K 2- 1- 8- 8-

  38. Homework • Draw orbital diagrams for elements # 4,6,9,15, and 26 • Draw Lewis Dot structures for elements 1-20 • Draw Bohr models for elements # 2, 3, 5, 9, and 16

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