1. Bohr Diagrams for Atoms

2. Showing Protons, Neutrons and Electron Arrangements for neutral atoms of the First 20 Elements

3. Niels Bohr (1885 – 1962) In 1913 Niels Bohr Developed a Model of the Atom

4. Niels Bohr (1885 – 1962) In 1913 Niels Bohr Developed a Model of the Atom in which electrons are found outside the nucleus,

5. Niels Bohr (1885 – 1962) In 1913 Niels Bohr Developed a Model of the Atom in which electrons are found outside the nucleus, where they occupy shells.

6. Period 1

7. Period 2

8. Period 1 Period 2 Period 3

9. Period 4 Period 1 Period 2 Period 3

10. Period 4 Period 1 Period 2 Period 3 Number of Protons = 6

11. Period 4 Period 1 Period 2 Period 3 Number of Protons = 6

12. Period 4 Period 1 Period 2 Period 3 Approximate number of protons plus neutrons in the most common form of the element

13. Period 4 Period 1 Period 2 Period 3 Number of protons + neutrons in the most common form of carbon = 12

14. Period 1 Period 2 Period 3 Carbon has 6 protons and 12–6 = 6 neutrons

15. Period 1 Period 2 Period 3 Number of protons + neutrons = 12 Carbon has 6 protons and 12–6 = 6 neutrons

16. Period 1 Period 2 Period 3 Carbon has 6 protons and 12–6 = 6 neutrons Number of protons + neutrons = 12

17. Period 1 Period 2 Period 3 Argon has 18 protons and 40–18 = 22 neutrons

18. Period 1 Period 2 Period 3 Argon has 18 protons and 40–18 = 22 neutrons

19. Period 1 Period 2 Period 3 Argon has 18 protons and 40–18 = 22 neutrons

20. Period 4 Period 1 Period 2 Period 3 Number of Electrons in a Neutral Atom = 6

21. Period 4 Period 1 Period 2 Period 3 Number of Electrons in a Neutral Carbon Atom = 6

22. Period 4 Period 1 Period 2 Period 3 Number of Electrons in a Neutral Carbon Atom = 6

23. Period 4 Period 1 Period 2 Period 3 Phosphorus has 15 protons, 15 electrons in a neutral atom, and 31–15 = 16 neutrons.

24. Period 4 Period 1 Period 2 Period 3 Phosphorus has 15 protons, 15 electrons in a neutral atom, and 31–15 = 16 neutrons.

25. Period 4 Period 1 Period 2 Period 3 Phosphorus has 15 protons, 15 electrons in a neutral atom, and 31–15 = 16 neutrons.

26. Period 4 Period 1 Period 2 Period 3 Phosphorus has 15 protons, 15 electrons in a neutral atom, and 31–15 = 16 neutrons.

27. Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e –

28. Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e –

29. Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e –

30. Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e –

31. Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – A lower shell must be completely filled, before electrons are added to the next shell.

32. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen

33. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 proton 1–1 = 0 neutrons

34. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 proton 1–1 = 0 neutrons

35. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 proton 1–1 = 0 neutrons

36. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 proton 1–1 = 0 neutrons

37. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 proton 1–1 = 0 neutrons

38. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 proton 1–1 = 0 neutrons

39. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 proton 1–1 = 0 neutrons

40. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen

41. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 e – in a neutral atom

42. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 e – in a neutral atom

43. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 e – in a neutral atom

44. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 e – in a neutral atom

45. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen 1 e – in a neutral atom An unpaired e –

46. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Hydrogen The Bohr Model for Hydrogen

47. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 1 proton 1–1 = 0 neutrons

48. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 protons 1–1 = 0 neutrons

49. 2 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 protons 1–1 = 0 neutrons

50. 2 p 2 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 protons 4–2 = 2 neutrons

51. 2 p 2 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 protons 4–2 = 2 neutrons

52. 2 p 2 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 protons 4–2 = 2 neutrons

53. 2 p 2 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 e – in a neutral atom

54. 2 p 2 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 e – in a neutral atom

55. 2 p 2 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 2 e – in a neutral atom

56. 2 p 2 n Period 1 Period 2 Period 3 Period 4 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 1 st Shell holds maximum 2 e – The Bohr Model for Helium

57. 2 p 2 n Period 1 Period 2 Period 3 Period 4 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 1 st Shell holds maximum 2 e –

58. 2 p 2 n Period 1 Period 2 Period 3 Period 4 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 1 st Shell holds maximum 2 e – The 1 st shell is completely filled

59. 2 p 2 n Period 1 Period 2 Period 3 Period 4 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 1 st Shell holds maximum 2 e – The 1 st shell is completely filled Helium is a Noble Gas

60. 2 p 2 n Period 2 Period 3 Period 4 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 1 st Shell holds maximum 2 e – Helium is a Noble Gas

61. 2 p 2 n Period 2 Period 3 Period 4 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Helium 1 st Shell holds maximum 2 e – Helium is a Noble Gas

62. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons

63. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons

64. 1 p 0 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons Add another shell Period 2

65. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons Add another shell

66. 1 p 0 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 protons 1–1 = 0 neutrons

67. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 protons 1–1 = 0 neutrons

68. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 protons 7–3 = 0 neutrons

69. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 protons 7–3 = 4 neutrons

70. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 protons 7–3 = 4 neutrons

71. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 e – in a neutral atom

72. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 e – in a neutral atom

73. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 e – in a neutral atom The first 2e – go into the 1 st shell

74. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons 3 e – in a neutral atom The 3 rd e – goes into the 2 nd shell

75. 3 p 4 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Lithium 1 proton 1–1 = 0 neutrons The Bohr Model for Lithium

76. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium 1 proton 1–1 = 0 neutrons

77. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium 9–4 = 5 neutrons

78. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium 4 e – in a neutral atom

79. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium 4 e – in a neutral atom

80. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium 4 e – in a neutral atom The first 2e – go into the 1 st shell

81. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium 4 e – in a neutral atom The 3 rd and 4 th e – s go into the 2 nd shell

82. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium The Bohr Model for Beryllium

83. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium The Bohr Model for Beryllium An electron pair

84. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium Another Possible Bohr Model for Beryllium

85. 4 p 5 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Beryllium Another Possible Bohr Model for Beryllium

86. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron

87. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron 11–5 = 6 neutrons

88. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron 5 e – in a neutral atom

89. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron 5 e – in a neutral atom The first 2e – go into the 1 st shell

90. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron 5 e – in a neutral atom The 3 rd and 4 th e –

91. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron 5 e – in a neutral atom And the 5 th e –

92. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron The Bohr Model for Boron

93. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron The Bohr Model for Boron An e – pair

94. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron The Bohr Model for Boron An unpaired e –

95. 5 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Boron Another Possible Bohr Model for Boron

96. 6 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Carbon

97. 6 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – 12–6 = 6 neutrons Carbon

98. 6 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – 6 e – in a neutral atom Carbon

99. 6 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – 6 e – in a neutral atom The first 2e – go into the 1 st shell Carbon

100. 6 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – 6 e – in a neutral atom The next 4 e – go into the 2 nd shell Carbon

101. 6 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Carbon The Bohr Model for Carbon

102. 6 p 6 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Carbon Another Possible Bohr Model for Carbon

103. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen

104. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen 14–7 = 7 neutrons

105. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen 7 e – in a neutral atom

106. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen 7 e – in a neutral atom

107. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen The Bohr Model for Nitrogen

108. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen 1 e – pair

109. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen 1 lone pair

110. 7 p 7 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Nitrogen 3 Unpaired e – s

111. 8 p 8 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Oxygen

112. 8 p 8 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Oxygen 16–8 = 8 neutrons

113. 8 p 8 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Oxygen 8 e – in a neutral atom

114. 8 p 8 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Oxygen 8 e – in a neutral atom

115. 8 p 8 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Oxygen The Bohr Model for Oxygen

116. 8 p 8 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Oxygen 2 lone pairs

117. 8 p 8 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Oxygen 2 unpaired e – s

118. 9 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Fluorine

119. 9 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Fluorine 19–9 = 10 neutrons

120. 9 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Fluorine 9 e – in a neutral atom

121. 9 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Fluorine 9 e – in a neutral atom

122. 9 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Fluorine The Bohr Model for Fluorine

123. 9 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Fluorine 3 lone pairs

124. 9 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Fluorine 1 unpaired e –

125. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon

126. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon 20–10 = 10 neutrons

127. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon 10 e – in a neutral atom

128. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon 10 e – in a neutral atom

129. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon The Bohr Model for Neon

130. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon 4 lone pairs

131. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon A stable octet

132. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon A stable octet

133. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon A completely filled 2 nd shell

134. 10 p 10 n Period 1 Period 2 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon A completely filled 2 nd shell Neon is a Noble Gas

135. 10 p 10 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon A completely filled 2 nd shell

136. 10 p 10 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Neon A completely filled 2 nd shell

137. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2

138. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 Add another shell

139. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 Add another shell

140. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2

141. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 23–11 = 12 neutrons

142. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom

143. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom

144. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom 2e– go into the 1 st shell

145. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom

146. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom 8e – go into the 2 nd shell

147. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom 8e – go into the 2 nd shell

148. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom 2e – go in shell 1 and 8e – in shell 2

149. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 11 electrons in a neutral atom Since shells 1 and 2 are filled, the last e – goes in shell 3

150. 11 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sodium Period 2 The Bohr Model for Sodium

151. 12 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Magnesium Period 2 24–12 = 12

152. 12 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Magnesium Period 2 12 electrons in a neutral atom

153. 12 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Magnesium Period 2 12 electrons in a neutral atom

154. 12 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Magnesium Period 2 The Bohr Model for Magnesium

155. 12 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Magnesium Period 2 Another Possible Bohr Model for Magnesium

156. 12 p 12 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Magnesium Period 2 Another Possible Bohr Model for Magnesium

157. 13 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Aluminum Period 2 27–13 = 14

158. 13 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Aluminum Period 2 13 electrons in a neutral atom

159. 13 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Aluminum Period 2 13 electrons in a neutral atom

160. 13 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Aluminum Period 2 The Bohr Model for Aluminum

161. 13 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Aluminum Period 2 Another Possible Bohr Model for Aluminum

162. 14 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Silicon Period 2 28–14 = 14

163. 14 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Silicon Period 2 14 electrons in a neutral atom

164. 14 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Silicon Period 2 14 electrons in a neutral atom

165. 14 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Silicon Period 2 The Bohr Model for Silicon

166. 14 p 14 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Silicon Period 2 Another Possible Bohr Model for Silicon

167. 15 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Phosphorus Period 2 31–15 = 16

168. 15 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Phosphorus Period 2 15 electrons in a neutral atom

169. 15 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Phosphorus Period 2 15 electrons in a neutral atom

170. 15 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Phosphorus Period 2 The Bohr Model for Phosphorus

171. 16 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sulphur Period 2 32–16 = 16

172. 16 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sulphur Period 2 16 electrons in a neutral atom

173. 16 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sulphur Period 2 16 electrons in a neutral atom

174. 16 p 16 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Sulphur Period 2 The Bohr Model for Sulphur

175. 17 p 18 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Chlorine Period 2 35–17 = 18

176. 17 p 18 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Chlorine Period 2 17 electrons in a neutral atom

177. 17 p 18 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Chlorine Period 2 17 electrons in a neutral atom

178. 17 p 18 n Period 1 Period 3 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Chlorine Period 2 The Bohr Model for Chlorine

179. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 40–18 = 22

180. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 18 electrons in a neutral atom

181. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 18 electrons in a neutral atom

182. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 The Bohr Model for Argon

183. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 Argon has a Stable Octet

184. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 The 3 rd shell has 8 e – s

185. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 The 3 rd shell has 8 e – s

186. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 The 3 rd shell has 8 e – s The 3 rd shell is completely filled. Argon is a noble gas.

187. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2 Period 3 The 3 rd shell has 8 e – s noble gas The 3 rd shell is completely filled. Argon is a noble gas.

188. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2

189. 18 p 22 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Argon Period 2

190. 19 p 21 n Period 1 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Potassium Period 2 Period 3 Period 4

191. 19 p 21 n Period 1 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Potassium Period 2 Period 3 Add another shell Period 4

192. 19 p 21 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Potassium Period 2 Period 3 40–19 = 21

193. 19 p 21 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Potassium Period 2 Period 3 19 electrons in a neutral atom

194. 19 p 21 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Potassium Period 2 Period 3 19 electrons in a neutral atom

195. 19 p 21 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Potassium Period 2 Period 3 The Bohr Model for Potassium

196. 20 p 20 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Calcium Period 2 Period 3 40–20 = 20

197. 20 p 20 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Calcium Period 2 Period 3 20 electrons in a neutral atom

198. 20 p 20 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Calcium Period 2 Period 3 20 electrons in a neutral atom

199. 20 p 20 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Calcium Period 2 Period 3 The Bohr Model for Calcium

200. 20 p 20 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Calcium Period 2 Period 3 Another Possible Bohr Model for Calcium

201. 20 p 20 n Period 1 Period 4 1 st Shell holds maximum 2 e – 2 nd Shell holds maximum 8 e – 3 rd Shell holds maximum 8 e – Calcium Period 2 Period 3 Another Possible Bohr Model for Calcium