1. Atomic Structure II Electron Configurations Barbara A. Gage PGCC CHM 1010

2. Atomic Orbitals Each electron is assigned to: Primary energy level (shell), n Orbital type in the shell (s,p,d,f) Specific orbital of the type Because of repulsion considerations only 2 electrons can occupy any orbital (spinning in opposite directions) Barbara A. Gage PGCC CHM 1010

3. Shell (n) # s orbitals # p orbitals # d orbitals # f orbitals Total e - 112 2138 313518 4135732 5135750 Atomic Shells and Orbitals Barbara A. Gage PGCC CHM 1010

4. This diagram shows the energy levels of the atomic orbitals. Electrons fill orbitals from bottom to top of the diagram. Barbara A. Gage PGCC CHM 1010

5. dark - filled, spin-paired light - half-filled no color-empty TA pg. 241 A vertical orbital diagram for the Li ground state. Silberberg, Principles of Chemistry The electron configuration is written as: 1s 2 2s 1 shell orbital # electrons in orbital Barbara A. Gage PGCC CHM 1010

6. Table 8.2 Silberberg, Principles of Chemistry Barbara A. Gage PGCC CHM 1010

7. Silberberg, Principles of Chemistry Barbara A. Gage PGCC CHM 1010

8. You can use a chart like this to determine the electron configuration. (But there is an easier way.) Barbara A. Gage PGCC CHM 1010

9. Figure 8.5 A periodic table of partial ground-state electron configurations. Silberberg, Principles of Chemistry Barbara A. Gage PGCC CHM 1010

10. Figure 8.6 The relation between orbital filling and the periodic table. Silberberg, Principles of Chemistry Barbara A. Gage PGCC CHM 1010

11. SAMPLE PROBLEM 8.2Determining Electron Configuration PLAN: SOLUTION: PROBLEM:Using the periodic table on the inside cover of the text (not Figure 8.12 or Table 8.4), give the full and condensed electrons configurations, partial orbital diagrams showing valence electrons, and number of inner electrons for the following elements: (a) potassium (K: Z = 19)(b) molybdenum (Mo: Z = 42)(c) lead (Pb: Z = 82) Use the atomic number for the number of electrons and the periodic table for the order of filling for electron orbitals. Condensed configurations consist of the preceding noble gas and outer electrons. (a) for K (Z = 19) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 [Ar] 4s 1 4s 1 condensed configuration partial orbital diagram full configuration There are 18 inner electrons. 3d4p Barbara A. Gage PGCC CHM 1010

12. SAMPLE PROBLEM 8.2 continued (b) for Mo (Z = 42) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 4d 5 [Kr] 5s 1 4d 5 (c) for Pb (Z = 82) [Xe] 6s 2 4f 14 5d 10 6p 2 condensed configuration partial orbital diagram full configuration 5s 1 4d 5 condensed configuration partial orbital diagram full configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 2 There are 36 inner electrons and 6 valence electrons. 6s 2 6p 2 There are 78 inner electrons and 4 valence electrons. 5p Barbara A. Gage PGCC CHM 1010

13. Configuration for Ions What is the electron configuration for Na + ? Na = 1s 2 2s 2 2p 6 3s 1 Na + = 1s 2 2s 2 2p 6 3s 1 What is the electron configuration for Se 2- ? Se = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4 Se 2- = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 Barbara A. Gage PGCC CHM 1010

14. Configuration for Ions Transitions metals have a twist… Fe = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 Fe 2+ = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 Fe 3+ = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 5 Barbara A. Gage PGCC CHM 1010