1. Ionization Energies Originated 11/20/11 Last revision 05/19/12 Mike Jones Pisgah High School Canton NC

2. Ionization energy The energy needed to remove an electron completely from at atom. Depends upon …. The attraction between the positively charged nucleus and the negatively charged electron. The repulsion between the negatively charged electrons.

3. Ionization energy The energy needed to remove an electron completely from at atom. F = kq 1 q 2 r2r2 Coulomb’s Law Force of attraction a constant the effective nuclear charge the charge of the electron the distance between the nucleus and the electron As applied to the atom Some of the attraction of the outermost electron to the nucleus is reduced because of repulsion between the outermost electron and the remaining electrons. The apparent charge on the nucleus is called the effective nuclear charge, Z eff.

4. The ionization energy is high when there is a strong force of attraction between the nucleus and the outermost electrons. With a low ionization energy, there is less attraction between the nucleus and the electron.

6. Helium has a very large ion ionization energy, which indicates a very strong attraction between the nucleus and the electron. That electron is at a lower energy, and a large amount of energy is needed to remove the electron. The ionization energy of lithium is very low, which indicates a weak attraction. That electron is already at a higher energy and little additional energy is needed to remove the electron.

7. Ionization energy is a periodic property. The peaks are the inert gases. The valleys are the alkali metals. See how the pattern repeats for each period

8. The ionization energy generally increases along a period as the atomic number increases and the charge on the nucleus increases. This produces more attraction between the nucleus and the electron, resulting in more energy being needed to remove the electron.

9. The ionization energy increases very little for the first row of the transition metals despite an increase in the number of protons. The effective nuclear charge of the transition metals increases only marginally, and the sizes of the atoms remain close to the same.

10. +

11. + 2

12. + 2

13. + 2

14. + 2

15. + 2

16. + 2

17. + 2

18. + 2

19. + 8 2

20. + 8 2

21. + 8 2

22. + 8 2

23. + 8 2

24. + 8 2

25. + 8 2

26. + 8 2

27. + 8 2 8

28. + 8 2 8

29. + 8 2 8 18

30. + 8 2 8

31. + 8 2 8

32. + 8 2 8

33. + 8 2 8 2 8 8 32

34. Q. Eight electrons are filling the second energy level. Why does the ionization energy increase along a period? A. The number of protons is increasing and Z eff increases.

35. Why are there “blips” in the ionization energies?

36. One hypothesis is that there are two energy sublevels, very close together, making up the second energy level.. Going from Be to B, goes from one sublevel to the other and less additional energy is needed to remove an electron from the sublevel with the greater energy.

37. Electrons in the lower sublevel Electrons in the higher sublevel One hypothesis is that there are two energy sublevels, very close together, making up the second energy level.. Going from Be to B, goes from one sublevel to the other and less additional energy is needed to remove an electron from the sublevel with the greater energy.

38. The same is true for the third energy level. Electrons in the lower sublevel Electrons in the higher sublevel

39. There are many limitations of the Bohr model, including the fact that the calculations work only for hydrogen. But there is one overriding reason why the Bohr model is so important to our study of the atom and the arrangement of electrons. The Bohr model tells us that electrons are located only in certain, discrete energy levels and that they can only change from one energy level to another by gaining or losing energy.

40. 1 2 3 4 The Bohr model of hydrogen. There are only a few discrete energy levels. The “excited electron” is located in one of these energy levels The ground-state electron is located in the lowest energy level.

41. n2n 2 12 28 318 432 550 The number of electrons in the n th energy level is given by 2n 2. The Bohr model showed only 8 electrons in the third energy level. Where are the other ten electrons? The Quantum mechanical model deals with mulit- electrons atoms with many more energy levels.

42. 1 2 3 4 Except for the first energy level, each energy level in the Bohr model is “subdivided” into two or more “sublevels.” n2n 2 12 28 318 432 550 n is the “principal quantum number, one of 4 numbers that uniquiely describe each electron in an atom The Quantum mechanical model has more energy levels available to electrons

43. n2n 2 12 28 318 432 550 In multi-electron atoms the original Bohr energy levels are split into sublevels. 1 2 3 4

44. n2n 2 12 28 318 432 550 In multi-electron atoms the original Bohr energy levels are split into sublevels. 1 2 3 4

45. n2n 2 12 28 318 432 550 In multi-electron atoms the original Bohr energy levels are split into sublevels. 1 2 3 4 Overlap between energy sublevels.

46. n2n 2 12 28 318 432 550 In multi-electron atoms the original Bohr energy levels are split into sublevels. 1 2 3 4 1s 2s 2p 3s 4s 3p 4p 3d 4d 4f The letters s, p, d and f are used to label the sublevels. s = sharp p = principal d = diffused f = fundamental

47. n2n 2 12 28 318 432 550 In multi-electron atoms the original Bohr energy levels are split into sublevels. 1 2 3 4 1s 2s 2p 3s 4s 3p 4p 3d 4d 4f sublevelnumber of electrons s2 p6 d10 f14 2 8 18 32 The letters s, p, d and f are used to label the sublevels.

48. Periodic table - Sublevels s p d f 2 6 10 14 How many electrons go in each region?

49. Since we can’t see atoms or the electrons we have know idea what they actually look like. Yet we need a way to represent the organization of electrons in an atom. Much like technicians use a schematic diagram to represent the components in an electronic circuit, chemists use the electron energy diagram to represent electrons in an atom.

51. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Electron Energy Diagram n2n 2 12 28 318 432 550 s2 p6 d10 f14 The electron energy diagram is a “schematic diagram” of an atom, representing the arrangement of electrons. It consists of numbers, letters and lines denoting the orbitals in the various energy sublevels.

52. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Electron Energy Diagram n2n 2 12 28 318 432 550 s2 p6 d10 f14 Each of the lines represents an “orbital” where up to two electrons can be located. The number is the principal quantum number, n.

53. An orbital is a “region in space” within an atom where up to two electrons can be located. An s-orbital is spherical. Two electrons. The p-orbitals are “dumbell” shaped. Each orbital contains two electrons, for a total of six The Shrodinger wave equation predicts the shape of the orbitals.

54. The five d-orbitals are shaped like this. Each orbital can contain two electrons, for a total of 10 electrons. The transition metals are filling the d-orbitals.

55. An orbital in the energy diagram is represented by a horizontal line. On the line we place two arrows, one pointing up and one point down, to represent the two electrons in the orbital. Orbital Orbital with one electron Orbital with two electrons Electrons, have the same charge and repel each other. How can two electrons coexist in an orbital where they are fairly close together? Electrons, have a property called spin, which has nothing to do with the electrons spinning. Spin is a magnetic property. Each electron acts like a tiny magnet. Orienting the electrons with opposite spin allows the electrons to occupy the same orbital.

56. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y Electron Energy Diagram for Arsenic Electrons with opposite spin are represented by up and down arrows. Each horizontal line represents an orbital, a region which can be occupied by up to two electrons. The electron energy diagram represents the arrangement of the electrons in their respective energy levels and sublevels.

57. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y Electron Energy Diagram for Arsenic Hund’s rule says that orbitals at the same energy each get one electron before the second electron is added to an orbital. Hund’s rule also says that all the electrons in the singly occupied orbitals will have the same spin. This is why all the arrows in the 4p are in different orbitals and pointed up.

58. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Electron Energy Diagram

59. 1s E n e r g y Electron Energy Diagram

60. 1s 2s 2p E n e r g y Electron Energy Diagram The second energy splits into two sublevels called “s” and “p”. An s-sublevel holds two electons. A p-sublevel holds up to six electrons in three orbitals.

61. 1s 2s 2p 3s 3p 3d E n e r g y Electron Energy Diagram The third energy splits into three sublevels, the “s”, the “p”, and the “d”. The d-sublevel holds up to ten electrons in five orbitals.

62. 1s 2s 2p 3s 4s 3p 4p 3d 4d 4f E n e r g y Electron Energy Diagram The fourth energy splits into four sublevels, the “s”, the “p”, the “d”, and the “f ”. The f-sublevel holds up to 14 electrons in seven orbitals. Notice that the 4s sublevel is lower in energy than the 3d sublevel.

63. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 4f 5d 5f E n e r g y Electron Energy Diagram Notice the overlap again in the 5s and 4d, and the location of the 4f sublevel.

64. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 5f 6d E n e r g y Electron Energy Diagram The 6s-sublevel is lower in energy than the 4f sublevel.

65. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Electron Energy Diagram The 7s-sublevel is lower in energy than the 5f sublevel. The energy sublevels are filled in order from lowest energy to highest energy.

66. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y The order in which the energy sublevels are filled follows the red line. Electron Energy Diagram This is called the Aufbau principle. Aufbau means “building up”, and refers to the building up of the atom one electron at a time.

67. Periodic table - Sublevels s p d f

68. Order in which the energy sublevels are filled.

69. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Electron Energy Diagram The order in which the orbitals are filled can also be predicted from the graph of ionization energy.

70. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s H

71. 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s He

72. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s Li

73. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s Be

74. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p B

75. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p C

76. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p N

77. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p O

78. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p F

79. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p Ne

80. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s Na

81. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s Mg

82. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p Al

83. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p Si

84. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p P

85. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p S

86. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p Cl

87. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p Ar

88. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s K

89. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s Ca

90. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Sc

91. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Ti

92. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d V

93. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Cr

94. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Mn

95. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Fe

96. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Co

97. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Ni

98. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Cu

99. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d Zn

100. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p Ga

101. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p Ge

102. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p As

103. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p Se

104. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p Br

105. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p Kr

106. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s Rb

107. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s Sr

108. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d Y

109. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d Tc

110. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d Cd

111. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p In

112. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p Sb

113. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p Xe

114. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p Cs

115. How to draw the energy diagram for an element. 1.Locate the element in the periodic table. 2.Note the sublevel of the last electron of the element. 3.Determine the principal quantum number of the last electron of the element. 4.Draw a blank energy diagram beginning with the 1s sublevel and continuing until you draw the target sublevel. 5.Determine the number of electrons in the target sublevel. 6.Draw arrows to represent the number of electrons in that sublevel. 7.Fill in all the orbitals below the target sublevel with up and down arrows representing the electrons with opposite spin.

116. 1.Locate the element in the periodic table. 2.Note the sublevel of the last electron of the element. 3.Determine the principal quantum number of the last electron of the element. 4.Draw a blank energy diagram beginning with the 1s sublevel and continuing until you draw the target sublevel. 5.Determine the number of electrons in the target sublevel. 6.Draw arrows to represent the number of electrons in that sublevel. 7.Fill in all the orbitals below the target sublevel with up and down arrows representing the electrons with opposite spin. Draw the energy diagram for zinc. Zinc has a total of 30 electrons, 10 of which are in the 3d sublevel, the highest sublevel. Draw the energy diagram up through the 3d sublevel. 1s 2s 2p 3s 4s 3p 3d

117. 1.Locate the element in the periodic table. 2.Note the sublevel of the last electron of the element. 3.Determine the principal quantum number of the last electron of the element. 4.Draw a blank energy diagram beginning with the 1s sublevel and continuing until you draw the target sublevel. 5.Determine the number of electrons in the target sublevel. 6.Draw arrows to represent the number of electrons in that sublevel. 7.Fill in all the orbitals below the target sublevel with up and down arrows representing the electrons with opposite spin. Draw the energy diagram for zinc. Draw in all ten electrons in the 3d sublevel. 1s 2s 2p 3s 4s 3p 3d

118. 1.Locate the element in the periodic table. 2.Note the sublevel of the last electron of the element. 3.Determine the principal quantum number of the last electron of the element. 4.Draw a blank energy diagram beginning with the 1s sublevel and continuing until you draw the target sublevel. 5.Determine the number of electrons in the target sublevel. 6.Draw arrows to represent the number of electrons in that sublevel. 7.Fill in all the orbitals below the target sublevel with up and down arrows representing the electrons with opposite spin. Draw the energy diagram for zinc. Draw in all the remaining electrons. 1s 2s 2p 3s 4s 3p 3d Energy diagram for zinc

119. 1.Locate the element in the periodic table. 2.Note the sublevel of the last electron of the element. 3.Determine the principal quantum number of the last electron of the element. 4.Draw a blank energy diagram beginning with the 1s sublevel and continuing until you draw the target sublevel. 5.Determine the number of electrons in the target sublevel. 6.Draw arrows to represent the number of electrons in that sublevel. 7.Fill in all the orbitals below the target sublevel with up and down arrows representing the electrons with opposite spin. Draw the energy diagram for zinc. 1s 2s 2p 3s 4s 3p 3d Draw the energy diagram for each of the following elements. 1. O 2. Al 3. V 4. Sn Energy diagram for zinc

120. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y Electron Energy Diagram for Arsenic We can represent the arrangement of electrons more simply by using the “electron configuration.” 1s 2, 2s 2 2p 6, 3s 2 3p 6, 4s 2, 3d 10, 4p 3

121. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y Electron Energy Diagram for Arsenic We can simplify the “electron configuration” even more by using the “inert gas core” to represent the electrons which do not take part in chemical reactions. 1s 2, 2s 2 2p 6, 3s 2 3p 6, 4s 2, 3d 10, 4p 3 Inert gas core – the inert gas is argon.

122. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y Electron Energy Diagram for Arsenic We can simplify the “electron configuration” even more by using the “inert gas core” to represent the electrons which do not take part in chemical reactions. 1s 2, 2s 2 2p 6, 3s 2 3p 6, 4s 2, 3d 10, 4p 3 Ar Write the symbol of the inert gas in square brackets.

123. 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p E n e r g y Electron Energy Diagram for Arsenic Write the electron configuration using the inert gas core for the following elements: 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi 1s 2, 2s 2 2p 6, 3s 2 3p 6, 4s 2, 3d 10, 4p 3 Ar

124. Write the electron configuration using the inert gas core for the following elements: 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 How many valence electrons does each element have? Valence electrons are the outer-most electrons which are involved in bonding.

125. 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 1. Al 3 The valence electrons have the highest principal quantum number. 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi

126. 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 1. Al 3 2. V5 The valence electrons have the highest principal quantum number. 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi Some transition metals have their valence electrons in the s and d orbitals.

127. 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 1. Al 3 2. V5 3. Br 7 The valence electrons have the highest principal quantum number. 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi

128. 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 1. Al 3 2. V5 3. Br 7 4. P 5 The valence electrons have the highest principal quantum number. 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi

129. 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 1. Al 3 2. V5 3. Br 7 4. P 5 5. Sn4 The valence electrons have the highest principal quantum number. 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi

130. 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 1. Al 3 2. V5 3. Br 7 4. P 5 5. Sn4 6. Bi5 The valence electrons have the highest principal quantum number. 1. Al 4. P 2. V 5. Sn 3. Br 6. Bi

131. 1.[Ne] 3s 2 3p 1 2.[Ar] 4s 2, 3d 3 3.[Ar] 4s 2, 3d 10, 4p 5 4.[Ne] 3s 2, 3p 3 5.[Kr] 5s 2, 4d 10, 5p 2 6.[Xe] 6s 2, 4f 14, 5d 10, 6p 3 1. Al 3 2. V5 3. Br 7 4. P 5 5. Sn4 6. Bi5 Look at the Roman numeral at the top of the column for each element. The valence electrons have the highest principal quantum number. Look at the Roman numeral at the top of the column for each element.

132. 1. Al 3 2. V5 3. Br 7 4. P 5 5. Sn4 6. Bi5 The Roman numeral at the top of each column on the period table tells the number of valence electrons.

133. Mike Jones Pisgah High School Canton NC 28716 mjones@haywood.k12.nc.us

134. + 1s 2s 2p 3s 4s 3p 4p 3d 4d 5s 5p 6s 4f 5d 6p 7s 5f 6d 7p E n e r g y Spare parts