1. { Electron Configurations Filling the atoms with electrons

2.  When you complete this presentation, you will be able to...  explain how to write the electron configuration for an atom using …  orbital notation  complete electron configuration  noble gas electron configuration Objectives

3.  We have learned how to determine the energy levels of electrons in elements.  We use the periodic table to tell if an electron is in …  a particular shell (1, 2, 3, 4, 5, 6, or 7) and  a particular orbital (s, p, d, or f). Introduction

4.  Now, we are going to learn exactly where the electrons go in an atom.  We have three guides that will help us figure this out.  The aufbau principle  The Pauli exclusion principle  Hund’s rule Introduction

5.  Electrons occupy orbitals of the lowest energy first.  We learned that the periodic table is a visualization of the energy levels of the orbitals in previous presentations.  Atomic orbitals start with 1s as the lowest energy and go up from there. The Aufbau Principle 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

6.  We add electrons into the 1s orbital,  then, to the 2s orbital,  then, to the 2p orbital,  then, to the 3s orbital,  and, so on.  We follow the periodic table. The Aufbau Principle 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

7.  This says that we can only have a maximum of two electrons in the same suborbital.  One must have a spin of +½ and one a spin of –½.  This means that we can have  2 electrons in each s orbital  6 electrons in each p orbital  10 electrons in each d orbital  14 electrons in each f orbital Pauli Exclusion Principle

8.  Hund’s rule uses the aufbau principle and the Pauli exclusion principle to show how we add electrons to the suborbitals.  We add a single electron to each suborbital before we double-up the electrons in a suborbital. Hund’s Rule

9.  For example, in adding electrons to the p-orbital across the 2 nd period Hund’s Rule B: 1s1s1s1s 2s2s2s2s 2p2p2p2p↑↓ ↑↓ ↑

10.  For example, in adding electrons to the p-orbital across the 2 nd period Hund’s Rule C: 1s1s1s1s 2s2s2s2s 2p2p2p2p↑↓ ↑↓ ↑ ↑

11.  For example, in adding electrons to the p-orbital across the 2 nd period Hund’s Rule N: 1s1s1s1s 2s2s2s2s 2p2p2p2p↑↓ ↑↓ ↑ ↑ ↑

12.  For example, in adding electrons to the p-orbital across the 2 nd period Hund’s Rule O: 1s1s1s1s 2s2s2s2s 2p2p2p2p↑↓ ↑↓ ↑ ↑↓↑

13.  For example, in adding electrons to the p-orbital across the 2 nd period Hund’s Rule F: 1s1s1s1s 2s2s2s2s 2p2p2p2p↑↓ ↑↓ ↑↓↑↑↓

14.  For example, in adding electrons to the p-orbital across the 2 nd period Hund’s Rule Ne: 1s1s1s1s 2s2s2s2s 2p2p2p2p↑↓ ↑↓ ↑↓↑↓ ↑↓

15.  The Schrödinger Equation describes the position of the electron in terms of total and potential energy.  The equation gives the position as a likelihood - a probability.  This then leads to the concept of the orbital as an electron cloud.  An electron cloud is the volume of space that contains an electron.  Different kinds of clouds are at different energy levels. Introduction

16.  There are different kinds of orbitals that make up each energy level.  Each energy level is assigned a principal quantum number.  From 1 to 7  This is the same as the number of periods in the periodic table.  This is no coincidence.  Each energy level is called a “shell.” Orbitals

17.  The 1 st shell contains one orbital:  the 1s orbital.  The 2 nd shell contains two orbitals:  the 2s orbital.  the 2p orbital.  The 3 rd shell contains three orbitals:  the 3s orbital  the 3p orbital  the 3d orbital Orbitals

18.  The 4 th shell contains four orbitals:  the 4s orbital.  the 4p orbital.  the 4d orbital.  the 4f orbital.  And, so on.  In actual practice, the 5 th shell only contains four orbitals (the s, p, d, and f orbitals), the 6 th shell only contains three orbitals (the s, p, and d orbitals), and the 7 th shell only contains two orbitals (the s and p orbitals). Orbitals

19.  Each orbital has its own:  shape  number of suborbitals  maximum number of electrons  energy level Orbitals

20.  The s orbital has one suborbital and it is shaped like a sphere.  The s orbital is perfectly symmetrical in all axes. Orbital Shapes

21.  The p orbital has three suborbitals and they are shaped like dumbbells.  Each p orbital is symmetrical to its particular axis. Orbital Shapes

22.  The d orbital has five suborbitals and they are shaped like 3D clover leaves.  Each d orbital is symmetrical to its particular plane. Orbital Shapes

23.  The f orbital has seven suborbitals and they are shaped like... ?  Each d orbital is symmetric in 3-dimensional space. Orbital Shapes

24.  We only need to remember the shapes of the s and p orbitals. Orbital Shapes

25.  Each orbital has a specific number of suborbitals available for electrons.  The s-orbital has 1.  The p-orbital has 3.  The d-orbital has 5.  The f-orbital has 7.  Each of the suborbitals can hold a maximum of 2 electrons. Suborbitals and Electrons

26.  Therefore, each orbital has a maximum number of electrons.  The s-orbital has 2 maximum.  The p-orbital has 6 maximum.  The d-orbital has 10 maximum.  The f-orbital has 14 maximum. Suborbitals and Electrons

27.  This corresponds to the width of each group on the periodic table.  The s block (Groups 1 and 2) is 2 elements wide. Suborbitals and Electrons

28.  This corresponds to the width of each group on the periodic table.  The p block (Groups 13 - 18) is 6 elements wide. Suborbitals and Electrons

29.  This corresponds to the width of each group on the periodic table.  The d block (Groups 3 - 12) is 10 elements wide. Suborbitals and Electrons

30.  This corresponds to the width of each group on the periodic table.  The f block (lanthanides and actinides) is 14 elements wide. Suborbitals and Electrons

31.  Each of the orbitals has an energy associated with it.  s-orbitals always have the lowest energy in a shell.  p-orbitals always have the next lowest energy in a shell.  d-orbitals always have the next lowest energy in a shell.  f-orbitals always have the highest energy in a shell. Orbitals and Energy

32.  We can do a diagram of the estimated energies of the shells and orbitals like this. Orbitals and Energy 1 st shell 2 nd shell 3 rd shell 4 th shell 1s1s 2s2s 2p2p 3s3s 3p3p 3d3d 4s4s 4p4p 4d4d 4f4f Lower energy Higher energy Actually, it is a little more complicated than this. But this gives you a good idea of the energy distribution in the electron shells of an atom.

33.  In reality, the upper orbitals of 3rd shell and above are higher energy than the lowest orbital of the next higher shell. Orbitals and Energy 1s1s 2s2s 2p2p 3s3s 3p3p 3d3d 4s4s 4p4p 4d4d 4f4f Energy

34. Orbitals and Energy 1s1s 2s2s 2p2p 3s3s 3p3p 3d3d 4s4s 4p4p 4d4d 4f4f Energy 5s5s 5p5p 5d5d 5f5f 6s6s 6p6p 6d6d 7s7s 7p7p From lowest energy to highest energy: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p This looks complicated. It would be complicated if we had to memorize this. But, we don’t. The periodic table is arranged in just this way.

35.  We start with 1s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

36.  We go to 2s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

37.  Then to 2p. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

38.  Then to 3s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

39.  Then to 3p. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

40.  Then to 4s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

41.  Then to 3d. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

42.  Then to 4p. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

43.  Then to 5s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

44.  Then to 4d. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

45.  Then to 5p. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

46.  Then to 6s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

47.  Then to 4f. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

48.  Then to 5d. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

49.  Then to 6p. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

50.  Then to 7s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

51.  Then to 5f. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

52.  Then to 6d. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

53.  And, finally, to 7s. Orbitals and Energy 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

54.  To follow the periodic table, we need to remember a couple of things.  s-orbitals begin in the 1 st shell. Orbitals and Energy ➀

55.  To follow the periodic table, we need to remember a couple of things.  p-orbitals begin in the 2 nd shell. Orbitals and Energy ➀ ➁

56.  To follow the periodic table, we need to remember a couple of things.  d-orbitals begin in the 3 rd shell. Orbitals and Energy ➀ ➁ ➂

57.  To follow the periodic table, we need to remember a couple of things.  f-orbitals begin in the 4 th shell. Orbitals and Energy ➀ ➁ ➂ ➃

58.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for oxygen, O Orbitals and Energy ➀ ➁ ➂ ➃

59.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for oxygen, O, we go 1s Orbitals and Energy ➀ ➁ ➂ ➃

60.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for oxygen, O, we go 1s, 2s Orbitals and Energy ➀ ➁ ➂ ➃

61.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for oxygen, O, we go 1s, 2s, 3p. Orbitals and Energy ➀ ➁ ➂ ➃

62.  If we want to find the orbitals available for an element, we just follow the periodic table.  Oxygen has electrons in the 3p orbital. Orbitals and Energy ➀ ➁ ➂ ➃

63.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu Orbitals and Energy ➀ ➁ ➂ ➃

64.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu, we go 1s Orbitals and Energy ➀ ➁ ➂ ➃

65.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu, we go 1s, 2s Orbitals and Energy ➀ ➁ ➂ ➃

66.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu, we go 1s, 2s, 2p Orbitals and Energy ➀ ➁ ➂ ➃

67.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu, we go 1s, 2s, 2p, 3s Orbitals and Energy ➀ ➁ ➂ ➃

68.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu, we go 1s, 2s, 2p, 3s, 3p Orbitals and Energy ➀ ➁ ➂ ➃

69.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu, we go 1s, 2s, 2p, 3s, 3p,4s Orbitals and Energy ➀ ➁ ➂ ➃

70.  If we want to find the orbitals available for an element, we just follow the periodic table.  For example, for copper Cu, we go 1s, 2s, 2p, 3s, 3p,4s, 3d. Orbitals and Energy ➀ ➁ ➂ ➃

71.  If we want to find the orbitals available for an element, we just follow the periodic table.  Copper has electrons in the 3d orbital. Orbitals and Energy ➀ ➁ ➂ ➃

72.  We don’t need to use the whole table if we remember where to start our count (s at 1, p at 2, d at 3, and f at 4).  For example, lead, Pb: Orbitals and Energy ➀ ➁ ➂ ➃

73.  We don’t need to use the whole table if we remember where to start our count (s at 1, p at 2, d at 3, and f at 4).  For example, lead, Pb: 2p Orbitals and Energy ➀ ➁ ➂ ➃

74.  We don’t need to use the whole table if we remember where to start our count (s at 1, p at 2, d at 3, and f at 4).  For example, lead, Pb: 2p, 3p Orbitals and Energy ➀ ➁ ➂ ➃

75.  We don’t need to use the whole table if we remember where to start our count (s at 1, p at 2, d at 3, and f at 4).  For example, lead, Pb: 2p, 3p, 4p Orbitals and Energy ➀ ➁ ➂ ➃

76.  We don’t need to use the whole table if we remember where to start our count (s at 1, p at 2, d at 3, and f at 4).  For example, lead, Pb: 2p, 3p, 4p, 5p Orbitals and Energy ➀ ➁ ➂ ➃

77.  We don’t need to use the whole table if we remember where to start our count (s at 1, p at 2, d at 3, and f at 4).  For example, lead, Pb: 2p, 3p, 4p, 5p, 6p. Orbitals and Energy ➀ ➁ ➂ ➃

78.  We don’t need to use the whole table if we remember where to start our count (s at 1, p at 2, d at 3, and f at 4).  Lead has electrons in the 6p orbital. Orbitals and Energy ➀ ➁ ➂ ➃

79.  There are different orbitals that make up each energy level.  Each level is assigned a principal quantum number from 1 to 7  Each level is called a “shell.”  Each orbital has its own shape, number of suborbitals, maximum number of electrons, and energy level. Summary

80.  We only need to remember the shapes of the s and p orbitals.  Each orbital has a specific number of suborbitals available for electrons, the s- orbital has 1, the p-orbital has 3, the d- orbital has 5, the f-orbital has 7.  Each of the suborbitals can hold a maximum of 2 electrons. Summary

81.  Therefore, each orbital has a maximum number of electrons: the s-orbital has 2 maximum, the p-orbital has 6 maximum, the d-orbital has 10 maximum, and the f- orbital has 14 maximum.  Each of the orbitals has an energy associated with it: s-orbitals always have the lowest energy in a shell, p-orbitals always have the next lowest energy in a shell, d-orbitals always have the next lowest energy in a shell, and f-orbitals always have the highest energy in a shell.  The periodic table is arranged in a way to be able to tell how the energies of orbitals and shells are arranged. Summary