1. To Do 6 th HW assignment due Wednesday, March 16, by 10 pm. Exam 2: Thursday, March 17, 7:00 pm. Sign up for conflict in 367 Noyes Lab. 1

2. A Comparison of the Radial Probability Distributions of the 2s and 2p Orbitals 2

3. A Comparison of the Probability Distributions of the 2s and 2p Orbitals 3

4. Radial Probability (3s, 3p, 3d) 4

5. Orbital Energy Levels for the Hydrogen Atom 5

6. The Orders of the Energies of the Orbitals in the First Three Levels of Polyelectronic Atoms 6

7. Electron Configurations for First 18 Elements 7

8. The Orbitals Being Filled for Elements in Various Parts of the Periodic Table 8

9. Valence Electrons Highest or outermost energy level electrons Where the chemistry “happens”! Look at principal quantum level n Sulfur: 1s 2 2s 2 2p 6 3s 2 3p 4 Valence electrons are in n = 3 level Valence electrons = 2 + 4 = 6 electrons 9

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11. Clicker Question How many unpaired electrons does sulfur contain in its ground state? (Hint: Draw an orbital diagram.) A)0 B)1 C)2 D)3 E)6 11

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13. Atomic Radius (Size) Generally increases down a group Hydrogen INCREASES! Francium Orbitals are getting larger and electrons are at higher energy levels 13

14. Atomic Radius (Size) Generally decreases across a row (period) – outer electrons in the same energy level Hydrogen Fluorine DECREASES! More protons in each element as you move across the row. More protons will create a stronger positive force, thus attracting the electrons more strongly. 14

15. Energy REQUIRED to remove an electron 15

16. Ionization Energy Generally decreases down a group Hydrogen DECREASES! Francium Orbitals are getting larger and electrons are at higher energy levels. Electrons are not as tightly bound by the nucleus at higher energy levels so it takes LESS energy to remove an outer electron. 16

17. Ionization Energy Generally increases across a row (period) – outer electrons in the same energy level Hydrogen Fluorine INCREASES! More protons in each element as you move across the row. More protons will create a stronger positive force, thus attracting the electrons more strongly and pulling them in closer to the nucleus, requiring MORE energy to remove an outer electron. 17

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19. Elements/Ions Do Not “Want” To Lose Electrons! 19

20. Cations = smaller Anions = larger 20

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22. Electron Affinity 22

23. Clicker Question Rank the following from smallest to largest atomic radius. a)Rb, Ca, Br, N b) Br, N, Rb, Ca c) N, Rb, Br, Ca d)N, Br, Ca, Rb e)Ca, Rb, N, Br 23

24. Clicker Question Rank the following from smallest to greatest ionization energy. a)Rb, Ca, Br, N b) Br, N, Rb, Ca c) N, Rb, Br, Ca d)N, Br, Ca, Rb e)Ca, Rb, N, Br 24