Notes lab 04a the atom complete notes

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Notes lab 04a the atom complete notes

  1. 1. The AtomNotes
  2. 2. The AtomFrom the Greek prefix A- meaning“not”And the Greek Root –tomos meaning“cut”Means “uncuttable”The ancient Greeks wanted to learn aboutthe smallest particle of matter
  3. 3. The AncientsDemocritusAristotle
  4. 4. Democritus
  5. 5. Democritus Believed that all matter consisted ofextremely small particles that could notbe divided. He called these particles atoms (fromthe Greek “ατοµος”, meaning “uncut” or“indivisible”).
  6. 6. Democritus He believed there were different types ofatoms with specific sets of properties. The atoms in liquids, for example, wereround and smooth The atoms in solids were rough and prickly
  7. 7. Aristotle
  8. 8. Aristotle He did not think there was a limit to thenumber of times matter could be divided He thought that all substances were builtup from only four elementsEarthAirFireWater
  9. 9. The ModernsDaltonThomsonRutherfordBohrSchrodinger & Heisenberg
  10. 10. Dalton
  11. 11. Dalton’s Model of the AtomCreated the 1st Atomic TheoryHis theory explained why theelements in a compound alwaysbond in the same way
  12. 12. Dalton’s Model of the AtomHe proposed the theory:All matter is made up of individualparticles, called atoms, whichcannot be divided.
  13. 13. Dalton’s Model of the AtomAll elements are composed ofsame atoms
  14. 14. Dalton’s Model of the AtomAll atoms of the same elementhave the same mass
  15. 15. Dalton’s Model of the AtomAtoms of different elementshave different masses.
  16. 16. Dalton’s Model of the AtomCompounds contain atoms ofmore than one element.
  17. 17. Dalton’s Model of the AtomIn a particularcompound, atoms of differentelements always combine inthe same way
  18. 18. The Dalton Model
  19. 19. The Dalton Model Video: http://www.youtube.com/watch?v=HFF-2wyyTKc&feature=results_video&playnext=1&list=PLF3AEE12BDB1E3858
  20. 20. J. J. Thomson
  21. 21. J. J. Thomson’s Model ofthe AtomThomson’s experiments withbeams of charged particles in asealed glass tube led him to theconclusion that atoms weremade of even smaller particles
  22. 22. J. J. Thomson’s Model of theAtomThomson reasoned:If the charge of an atom isneutral, the atom must containequal amounts of both positiveand negative charges
  23. 23. The Thomson Model Thomson said thatnegative chargeswere evenlyscattered throughoutan atom filled with apositively chargedmass of matter.
  24. 24. The Thomson Model Called the“Plum PuddingModel” after apopular dessertof the time
  25. 25. The Thomson Model Video: http://www.youtube.com/watch?v=JwdGFZA3WOs
  26. 26. Rutherford
  27. 27. Rutherford’s Model of theAtomRutherford discovered thaturanium emits fast-movingparticles with a positive charge.He called them alpha particles.
  28. 28. Rutherford’s Model of theAtomIn an experiment he charted thepath of alpha particles after theypassed through a thin layer ofgold foil and a number of theparticles were deflected.Many more thanexpected, sometimes by morethan 90°.
  29. 29. Rutherford’s Model of theAtomProved most of an atom isactually empty space!
  30. 30. Rutherford’s Model of theAtomThe positive charge of an atommust be concentrated in a verysmall central area that he calledthe nucleus.
  31. 31. Rutherford’s Model of theAtomFurther experiments determinedthat the positive charge of anatom is by the number ofprotons in the nucleus.
  32. 32. Rutherford’s Model of theAtomEach proton has a charge of +1.
  33. 33. The Rutherford Model
  34. 34. Rutherford’s Model of theAtom and Gold Foil Test
  35. 35. Rutherford’s Model Video Nucleus of an Atom
  36. 36. Niels Bohr
  37. 37. The Bohr Model of theAtom In Bohr’s model, electronsmove with constant speed infixed orbits around thenucleus, like planets around asun.
  38. 38. The Bohr Model of the Atom Electrons gain or lose energywhen they move between orbitsor energy levels. Energy levelsare like stairs on a staircase orshelves in a bookshelf
  39. 39. The Bohr Model of the Atom Evidence for discrete, uniqueenergy levels comes from thelight given off when energy isadded to the atoms of anelement (such as whenfireworks explode or electricityis added to a neon light).
  40. 40. The Bohr Model of the Atom No two elements have thesame set of energy levels, sothe emission pattern can beused to identify the element.
  41. 41. The Bohr Model of the Atom Video” The Niels Bohr Rap
  42. 42. The Bohr Model
  43. 43. Schrodinger &Heisenberg
  44. 44. Schrodinger & HeisenbergThese scientists discovered thatelectrons are less predictablethan in Bohr’s model of fixedorbits.
  45. 45. Schrodinger & HeisenbergAtoms gain or lose energy.when electrons move from oneenergy level to another
  46. 46. Schrodinger & HeisenbergThey use an electron cloudmodel to show the most likelylocations for electrons as theymove around the nucleus.
  47. 47. Schrodinger & HeisenbergThe electron cloud representsall the orbitals in an atom.
  48. 48. Schrodinger & HeisenbergAn orbital is a region of spacearound the nucleus where anelectron is likely to be found.
  49. 49. Schrodinger & HeisenbergOrbitals come in differentsizes, shapes, and locations
  50. 50. Schrodinger & HeisenbergAn electron configuration is thearrangement of electrons in theorbitals of an atom.
  51. 51. Schrodinger & Heisenberg The most stable electronconfiguration is the one in whichthe electrons are in orbitals withthe lowest possible energies
  52. 52.  Video : Change of Atom-Dalton, Thomson,Rutherford, Bohr
  53. 53. The Electron Cloud Model
  54. 54. The Electron Cloud Model Video: electron cloud model
  55. 55. The Nature of Science Each scientist was correct for histime and ability to makeobservations. As improvements in technologycame about, each later scientistproved the previous scientist(s)slightly incorrect.
  56. 56. The Nature of Science Now there is a totally differentmodel of the atom from the firstmodel presented by Dalton. Only some of the theories of eachscientist remain. In general…
  57. 57. The Nature of Science As the ability tomake betterobservationsimproves, the newknowledge maysupport or disprovewhat we have heldto be true.
  58. 58. The Nature of Science As the ability to make betterscientific observations improved, Atomic theory changed over time Scientists improved uponprevious scientists theories byproving the correct and disprovingthe incorrect
  59. 59. The Nature of Science From Dalton’s solid sphere thatbonded the same way all thetime… To Thomson’s “Plum Pudding “model of equal amounts ofpositive and negative charges…
  60. 60. The Nature of Science Then Rutherford proved that theequal charges were separated byvast space in a nucleus andorbiting electrons And Bohr gave order to theorbiting electrons saying that theymaintained constant orbits
  61. 61. The Nature of Science .

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