1. The Structure of an Atom

2. What were ancient “chemists” called? Alchemists

3. What did they do? Depends where they lived- make fireworks, make the philosophers stone, turn things into gold…

4. Who was the first person to come up with the word atom? Democritus

5. What did he say? The world was made up of tiny, indivisible particles (atomos).

6. Who was the next guy to come along in chemistry? John Dalton

7. What did John Dalton say? He had his atomic theory.

8. What is a theory? It is a explanation as to why an experiment may give certain results.

9. What is a law? A short statement explaining what will happen in a given situation.

10. What is the difference between a theory and a law? Laws are SHORT descriptions. Theories are LONG explanations.

11. What is Dalton’s Atomic Theory? It explains the previous laws.

12. How many parts of the atomic theory are there? 5 Johnny 5 is alive!

13. What is the first part? All matter is made of atoms.

14. The second? Atoms of different elements differ by their mass, size and other properties.

15. The third? Atoms cannot be created, destroyed, or divided.

16. The fourth? Atoms combine in ratios to form compounds.

17. The fifth? Chemical reactions require atoms to combine, separate, or rearrange.

18. How was Dalton wrong? Atoms are divisible All atoms of an element are not identical.

19. What is an atom? A piece of matter that can not be broken down any further and still have the characteristics of the element.

20. How small is an atom? So small we can’t even take a picture of it.

21. If you made an atom the size of an orange, you would have to make an orange the size of the earth to keep scale!

22. Who was the first guy to prove atoms could be broken down into smaller pieces? J.J. Thomson

23. What did he do? Discover the electron.

24. How did he do that? He was playing with electricity and matter.

25. What tool did he use? A cathode ray tube.

26. Cathode Ray Tubes and TV http://www.youtube.com/watch?v=HIjlzyn_2 H8

27. How did he arrive at his conclusion? He figured out there were negatively charged particles in an atom.

28. What did he call these negatively charged particles? Electrons.

29. Where did they think electrons were located? All throughout the atom. The plum pudding model

30. What was discovered next? Protons.

31. Who did that? Ernest Rutherford

32. How did Rutherford discover protons? The Gold Foil Test

33. Where are protons located? In the center of the atom.

34. What is the center of the atom called? The nucleus

35. How big is the nucleus compared to the rest of the atom? Very small

36. How did that change the way they thought an atom looked? The nucleus was in the center of the atom

37. What is the charge of a proton? Positive

38. How does the size of a proton compare to an electron? A proton is about 1836 times larger.

39. What is the other part of an atom? Neutrons.

40. What charge do they have? None-neutral

41. How big are they? About the same size as a proton

42. What hold the protons and neutrons together? Nuclear forces

44. How do I find the number of protons? It’s the atomic number.

45. Will the number of protons ever change? No! It will never, ever change.

46. How do I find the number of electrons in an atom? If there is no charge, they are equal to the number of protons. (+ = -)

47. How do I find the number of neutrons? Round the PT mass to a WHOLE number. Atomic Mass - atomic number= Neutrons

48. Practice!!! Find the number of p +, n o, and e - for the following…  Sulfur  Lawrencium  Sc

49. What is an isotope? An atom that has different numbers of neutrons

50. Do the isotopes of the same atoms all act the same? Yes! The only difference is the number of neutrons

51. What is the ONLY difference between isotopes? The numbers of neutrons

52. What is the mass number? Exact mass of the atom Mass number = protons + neutrons

53. Check it out! 17 OExact Oxygen-17Mass 17 O O-17 Atomic Number 8

54. What is the difference between the mass given in an isotope and the atomic mass on the periodic table? An isotope gives the exact mass. The PT is an average of all the known isotopes.

55. Find the number of p +,e -, and n o in the following: 94 Nb Germanium-75 Manganese-55 51 130 Sb

56. How do I find the most common isotope of an atom? By using the rounded mass from the periodic table.

57. Look it up! What is the most common isotope of…  Oxygen  Tin  Calcium  Bromine  Tungsten

58. What is average atomic mass? The weighted average mass of all the common isotopes of an atom.

59. How do I solve for average atomic mass? Convert the percent abundance to a decimal. (relative abundance – RA) Multiply the RA by the mass for each isotope. Add all together. (RA x mass)+(RA x mass)+(RA x mass)…etc.

60. Solve it! Rubidium has two common isotopes, 85 Rb and 87 Rb. If the abundance of 85 Rb is 72.2% and the abundance of 87 Rb is 27.8%, what is the average atomic mass of rubidium?

61. Solve it! Uranium has three common isotopes. If the abundance of 234 U is 0.01%, the abundance of 235 U is 0.71%, and the abundance of 238 U is 99.28%, what is the average atomic mass of uranium?

62. Solve it! Titanium has five common isotopes: 46 Ti (8.0%), 47 Ti (7.8%), 48 Ti (73.4%), 49 Ti (5.5%), 50 Ti (5.3%). What is the average atomic mass of titanium?

63. What unit is used for atomic mass or mass number? Atomic Mass Units (amu)

64. What is amu? It was figured out using carbon, 1/12 of the mass of a carbon atom. (The mass of a proton or neutron)

65. What is visible light? The portion of the EM Spectrum that you can see.

66. What is part of the visible light spectrum? ROY G BIV (the colors of a rainbow)

67. What happens when white light hits a prism? It separates by frequency into the rainbow.

68. What does this have to do with chemistry? It leads to the quantum theory.

69. What is a quantum? The minimum amount of energy that can be gained or lost by an atom.

70. What did this lead to? Light is not really a wave, but a quanta.

71. So what…. They are little packets of energy.

72. What did Einstein propose? That light was these little packets of energy called photons.

73. What happens with the photons? When an atom gets excited it releases light.

74. What is this called? The electron emission spectrum.

75. What is the electron emission spectrum? A kind of atomic fingerprint that is extremely useful in identifying elements.

77. Why do they emit light? The energy is absorbed and then released as light.

78. What did Neils Bohr do for atomic structure? He believed that electrons move in energy levels.

79. What is an energy level? The orbit the electron is in.

80. How do I figure out energy levels? Use the periodic table. The period number is how many energy levels there are.

81. How do I figure out how many electrons go on each level? Use the periodic table! 2, 8, 8, 18, 18, 32, 32

82. Practice! Draw a Bohr Model for  Chromium

83. What is a valence electron? The electrons on the outermost energy level.

84. How do I find the number of valence electrons? For Bohr Models… Start at the left of the period, and count over to the element.

85. Practice! Find the number of valence electrons in the following…  Calcium  Arsenic  Neodymium  Lithium

86. What happens when an electron jumps energy levels? It emits light.

87. Do we still think an atom looks like this today? No, now we have Schrödinger's quantum model.

88. How do we know electrons exist? Through a lot of math… Schrödinger’s equation

89. Where can we find electrons now? In orbitals

90. What is an orbital? A region of the atom that you are most likely to find an electron.

91. What is the Heisenburg uncertainty principle? It is impossible to know both the speed and location of an electron at any given moment.

92. What are the different types of orbitals? s p d f

93. What do they look like? s is spherical p is dumbbell shaped d is clover shaped f are complicated

96. Now put it all together… What an Atom Looks Like

97. Are the orbitals divided up? Yes, they are divided into sublevels.  s has 1  p has 3  d has 5  f has 7

98. What are the three rules I need to use to fill electron diagrams? Hund’s Rule Pauli Exclusion Principle Aufbau Principle

99. What is the Aufbau Principle? Electrons fill the lowest energy level first

100. Where does the f block go? The order goes:  6s-4f-5d  7s-5f-6d

102. What is the Pauli Exclusion Principle? An orbital can only hold 2 electrons, spinning in opposite directions

103. How do we draw an orbital? Each orbital is a _______

104. How do we show an electron in an orbital diagram? As an arrow

105. What is Hund’s Rule? Bus Seat Rule Orbitals are filled with one electron before a second electron can be added.

106. Sum it all up: Use the PT to fill in the correct order. There is one 1 s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals. (orbital are lines) Every orbital holds 2 e - (electrons are arrows) Fill each orbital before giving a second e -

107. Practice with orbital diagrams! Draw an orbital diagram for  Chlorine  Titanium

109. Are the arrows always necessary? No, That is just for the electron spin (orbital) diagrams

110. What do all the letters and numbers mean? Energy Level# of Electrons Shape of orbital 3d 8

111. Practice with electron configurations… Write electron configurations for the following  Nickel  Aluminum

113. How do I write the configurations shorter? Noble Gas Configuration

114. What is a noble gas? An element in the 18 th Group  He  Ne  Ar  Kr  Xe  Rn

115. How do I choose the noble gas? Use the noble gas that is on the last FULL period

117. Where to I start back up from? The period number that the element lives in

118. Practice with noble gas configurations… Write noble gas configurations for the following  Tellurium  Rutherfordium

119. What is a Lewis Dot diagram? It is the element symbol with the valence electrons placed around it. X

120. What is the shortcut to finding the valence electrons? Count over to the element, but skip the D- Block elements. SKIP!

121. Why skip the d-block elements? The electrons are actually in an inner energy level (per Aufbau). Only s and p electrons can be valence.

122. How many dots can go on each “side”? 2, for a total of 8

123. How do I place the electrons around the symbol? Start on one side, and fill the dots one per side. Double only if necessary. Like Hund’s rule

124. Practice! Draw Lewis Dot Structures for the following  Tin  Oxygen  Magnesium