The Atom Democritus Invisible Immortal Indivisible units
Aristotle Continuous matter
 
Joseph Proust (1754 – 1826) Law of Definite Proportions
Law of Definite Proportions Copper Carbonate: Regardless of the source, a compound always has the same proportion of eleme...
Law of Definite Proportions Copper Carbonate: CuCO 3  ->  Copper  +  Carbon  +  Oxygen
Law of Definite Proportions Copper Carbonate: CuCO 3  ->  Copper  +  Carbon  +  Oxygen   51.36%  9.72%   38.85%
Antoine Lavoisier Law of Conservation of Mass
Antoine Lavoisier Law of Conservation of Mass
Antoine Lavoisier Accounting for Oxygen gas
John Dalton Law of Multiple Proportions
Law of Multiple Proportions CO  and CO 2 H 2 O and H 2 O 2 NH 3  and N 2 H 4
Law of Multiple Proportions NH 3  and N 2 H 4 N 2   +  3 H 2   --->  NH 3 N 2   +  2 H 2   ---->  N 2 H 4
Law of Multiple Proportions NH 3  and N 2 H 4 N 2   +  3 H 2   --->  NH 3 28 g 6 g 34 g N 2   +  2 H 2   ---->  N 2 H 4 28...
Law of Multiple Proportions When elements combine to form more than one compound, different masses of one element compared...
Law of Multiple Proportions CO and CO 2 2 C  +  O 2   --->  2 CO 24 g 32 g 56 g C  +  O 2   ---->  CO 2 12 g    32 g 44 g
Dalton’s Five Principles <ul><li>Matter is made of atoms </li></ul><ul><li>All atoms of one element are the same </li></ul...
What is an Atom?
Cathode Rays <ul><li>William Crookes </li></ul>
CRTs
Stream of Charged Particles
How much smaller? Robert Millikan found that the particles were 1/1840 the size of the Hydrogen atom
Plum Pudding Model Negatively charged particles embedded in a positively charged ball of matter.
The Discovery of Electrons J.J. Thomson found that the cathode ray particles were much smaller than the H atom
Rutherford’s Gold Foil experiment Ernest Rutherford directed alpha particles at gold foil
Planetary Model
The Discovery of the Neutron 1932  Finds particle with no charge that has a mass of 1 atomic mass unit
Atomic Number <ul><li>Identification  Number </li></ul><ul><li>NUMBER  </li></ul><ul><li>OF PROTONS </li></ul>
Atomic Numbers
Atomic Masses <ul><li>Number of Protons ( ATOMIC NUMBER ) </li></ul><ul><ul><ul><ul><li>+ </li></ul></ul></ul></ul><ul><li...
Dalton’s Atoms
Atoms
Atomic Symbols Mass Number A = Sum of protons and neutrons Atomic number, Z  =  # of protons
Atomic Symbols Mass Number A = Sum of protons and neutrons Atomic number, Z  =  # of protons The number of neutrons for an...
Writing Atomic Symbols Symbol Atomic mass protons neutrons 22 ???? ????? ????? 20 26 11 ???? 6 ???? ????? ??????
Writing Atomic Symbols Symbol Atomic mass protons neutrons 22 10 12 46 20 26 11 5 6 64 30 34
Isotopes Same atomic number Different Mass number Different # neutrons
Isotopes
Relative abundance Bromine:  35 protons Br-79 Br-81 50.697% 49.317%
Relative abundance Bromine:  35 protons (79)(0.50697)  +  (81)(0.49317)  = 40  +  39.9  =  79.9 Br-79 Br-81 50.697% 49.317%
Listed Atomic Massed are Weighted Averages 35 Br 79.9
Same atomic mass??
What about Electrons? Why don’t electrons crash into the Nucleus?
Bohr Model of the Atom Niels Bohr 1913
Allowable Energy Transitions
Electromagnetic Spectrum
Properties of Waves As Wavelength increases, Frequency decreases. Wavelength x Frequency =  λ   x  ν  = velocity of Light ...
Emission Spectra
Atomic Emission Spectra
Schrödinger probability functions S orbital
P orbitals 3 types of p orbitals
D orbitals 5 types of d orbitals
How can electrons be ordered?
Energy Levels <ul><li>Aufbau (Building up) </li></ul><ul><li>  Principle </li></ul><ul><li>An electron must fill the orbit...
Energy Levels
Orbital Shapes S orbitals P orbitals
Orbital Shapes D orbitals F orbitals
Quantum Numbers <ul><li>n Principal Quantum number Energy    Level </li></ul><ul><li>l Angular Momentum Quantum Shape numb...
Spin States
Pauli exclusion Principle <ul><li>No two electrons in the same atom may have the same set of four quantum numbers; </li></...
Hund’s Rule <ul><li>Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second ...
Groups <ul><li>Dozen </li></ul><ul><li>Pair  Quartet </li></ul>
The Mole <ul><li># of atoms in 12 grams of Carbon-12 atoms </li></ul>
Molar Mass <ul><li>Mass of one MOLE of pure substance </li></ul><ul><li>Helium:  4.00 grams  -------> 4 grams per mole </l...
Size of the Atom <ul><li>Diameter of an atom  =  10 -10  m </li></ul><ul><li>250,000,000 atoms in One Inch </li></ul>
Size of the Atom <ul><li>1 atomic mass unit  =  mass of one proton, neutron </li></ul><ul><li>= 1.66 x 10 -24  grams </li>...
Avogadro’s Number <ul><li>There are 6.02 x 10 23  particles in a mole of any substance. </li></ul>
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Chem Unit2

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Chem Unit2

  1. 1. The Atom Democritus Invisible Immortal Indivisible units
  2. 2. Aristotle Continuous matter
  3. 4. Joseph Proust (1754 – 1826) Law of Definite Proportions
  4. 5. Law of Definite Proportions Copper Carbonate: Regardless of the source, a compound always has the same proportion of elements
  5. 6. Law of Definite Proportions Copper Carbonate: CuCO 3 -> Copper + Carbon + Oxygen
  6. 7. Law of Definite Proportions Copper Carbonate: CuCO 3 -> Copper + Carbon + Oxygen 51.36% 9.72% 38.85%
  7. 8. Antoine Lavoisier Law of Conservation of Mass
  8. 9. Antoine Lavoisier Law of Conservation of Mass
  9. 10. Antoine Lavoisier Accounting for Oxygen gas
  10. 11. John Dalton Law of Multiple Proportions
  11. 12. Law of Multiple Proportions CO and CO 2 H 2 O and H 2 O 2 NH 3 and N 2 H 4
  12. 13. Law of Multiple Proportions NH 3 and N 2 H 4 N 2 + 3 H 2 ---> NH 3 N 2 + 2 H 2 ----> N 2 H 4
  13. 14. Law of Multiple Proportions NH 3 and N 2 H 4 N 2 + 3 H 2 ---> NH 3 28 g 6 g 34 g N 2 + 2 H 2 ----> N 2 H 4 28 g 4 g 32 g
  14. 15. Law of Multiple Proportions When elements combine to form more than one compound, different masses of one element compared to the mass of the other element are small whole number ratios.
  15. 16. Law of Multiple Proportions CO and CO 2 2 C + O 2 ---> 2 CO 24 g 32 g 56 g C + O 2 ----> CO 2 12 g 32 g 44 g
  16. 17. Dalton’s Five Principles <ul><li>Matter is made of atoms </li></ul><ul><li>All atoms of one element are the same </li></ul><ul><li>Atoms of different elements are different </li></ul><ul><li>Atoms combine to form compounds </li></ul><ul><li>Atoms are rearranged in chemical reactions but not created nor destroyed </li></ul>
  17. 18. What is an Atom?
  18. 19. Cathode Rays <ul><li>William Crookes </li></ul>
  19. 20. CRTs
  20. 21. Stream of Charged Particles
  21. 22. How much smaller? Robert Millikan found that the particles were 1/1840 the size of the Hydrogen atom
  22. 23. Plum Pudding Model Negatively charged particles embedded in a positively charged ball of matter.
  23. 24. The Discovery of Electrons J.J. Thomson found that the cathode ray particles were much smaller than the H atom
  24. 25. Rutherford’s Gold Foil experiment Ernest Rutherford directed alpha particles at gold foil
  25. 26. Planetary Model
  26. 27. The Discovery of the Neutron 1932 Finds particle with no charge that has a mass of 1 atomic mass unit
  27. 28. Atomic Number <ul><li>Identification Number </li></ul><ul><li>NUMBER </li></ul><ul><li>OF PROTONS </li></ul>
  28. 29. Atomic Numbers
  29. 30. Atomic Masses <ul><li>Number of Protons ( ATOMIC NUMBER ) </li></ul><ul><ul><ul><ul><li>+ </li></ul></ul></ul></ul><ul><li>Number of Neutrons </li></ul><ul><li>ATOMIC MASS </li></ul>
  30. 31. Dalton’s Atoms
  31. 32. Atoms
  32. 33. Atomic Symbols Mass Number A = Sum of protons and neutrons Atomic number, Z = # of protons
  33. 34. Atomic Symbols Mass Number A = Sum of protons and neutrons Atomic number, Z = # of protons The number of neutrons for any atom will be the difference between A and Z (A – Z = # neutrons)
  34. 35. Writing Atomic Symbols Symbol Atomic mass protons neutrons 22 ???? ????? ????? 20 26 11 ???? 6 ???? ????? ??????
  35. 36. Writing Atomic Symbols Symbol Atomic mass protons neutrons 22 10 12 46 20 26 11 5 6 64 30 34
  36. 37. Isotopes Same atomic number Different Mass number Different # neutrons
  37. 38. Isotopes
  38. 39. Relative abundance Bromine: 35 protons Br-79 Br-81 50.697% 49.317%
  39. 40. Relative abundance Bromine: 35 protons (79)(0.50697) + (81)(0.49317) = 40 + 39.9 = 79.9 Br-79 Br-81 50.697% 49.317%
  40. 41. Listed Atomic Massed are Weighted Averages 35 Br 79.9
  41. 42. Same atomic mass??
  42. 43. What about Electrons? Why don’t electrons crash into the Nucleus?
  43. 44. Bohr Model of the Atom Niels Bohr 1913
  44. 45. Allowable Energy Transitions
  45. 46. Electromagnetic Spectrum
  46. 47. Properties of Waves As Wavelength increases, Frequency decreases. Wavelength x Frequency = λ x ν = velocity of Light = c
  47. 48. Emission Spectra
  48. 49. Atomic Emission Spectra
  49. 50. Schrödinger probability functions S orbital
  50. 51. P orbitals 3 types of p orbitals
  51. 52. D orbitals 5 types of d orbitals
  52. 53. How can electrons be ordered?
  53. 54. Energy Levels <ul><li>Aufbau (Building up) </li></ul><ul><li> Principle </li></ul><ul><li>An electron must fill the orbital </li></ul><ul><li>With the lowest energy first. </li></ul>
  54. 55. Energy Levels
  55. 56. Orbital Shapes S orbitals P orbitals
  56. 57. Orbital Shapes D orbitals F orbitals
  57. 58. Quantum Numbers <ul><li>n Principal Quantum number Energy Level </li></ul><ul><li>l Angular Momentum Quantum Shape number </li></ul><ul><li>n Magnetic Quantum number Spin </li></ul>
  58. 59. Spin States
  59. 60. Pauli exclusion Principle <ul><li>No two electrons in the same atom may have the same set of four quantum numbers; </li></ul><ul><li>Electrons in the same orbital must have opposite spins. </li></ul>
  60. 61. Hund’s Rule <ul><li>Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron. All electrons in singly occupied orbitals must have the same spin state </li></ul>
  61. 62. Groups <ul><li>Dozen </li></ul><ul><li>Pair Quartet </li></ul>
  62. 63. The Mole <ul><li># of atoms in 12 grams of Carbon-12 atoms </li></ul>
  63. 64. Molar Mass <ul><li>Mass of one MOLE of pure substance </li></ul><ul><li>Helium: 4.00 grams -------> 4 grams per mole </li></ul><ul><li>Lithium 6.94 grams ---------> 6.94 grams per mole </li></ul><ul><li>Mercury 200.59 grams -------> 200.59 grams per mole </li></ul>
  64. 65. Size of the Atom <ul><li>Diameter of an atom = 10 -10 m </li></ul><ul><li>250,000,000 atoms in One Inch </li></ul>
  65. 66. Size of the Atom <ul><li>1 atomic mass unit = mass of one proton, neutron </li></ul><ul><li>= 1.66 x 10 -24 grams </li></ul>
  66. 67. Avogadro’s Number <ul><li>There are 6.02 x 10 23 particles in a mole of any substance. </li></ul>

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