3. Within an energy level (n = 1, 2, 3, 4…), there exists n types of orbitals and n 2 sublevels. nOrbital types One s-orbital Three p-orbitals One s-orbital Three p-orbitals Five d-orbitals One s-orbital Seven f-orbitals Three p-orbitals Five d-orbitals

4. Within an energy level (n = 1, 2, 3, 4…), there exists n types of orbitals and n 2 sublevels. nOrbital types One s-orbital Three p-orbitals One s-orbital Three p-orbitals Five d-orbitals One s-orbital Seven f-orbitals Three p-orbitals Five d-orbitals Note: Each orbital can hold two electrons #e Total #e in energy level, n 2 e 3 x 2 e = 6 e 2 e 3 x 2 e = 6 e 5 x 2 e = 10 e 2 e 7 x 2 e = 14 e

5. y x z Recall: The shape of the orbital defines the region in space in which there is a 90% probability of finding the electron(s) in that orbital. The s-orbital is sphere shaped

6. x y z x y z x y z pxpx pzpz pypy The three p-orbitals are oriented along the x, y and z axes and can hold a maximum of 2 electrons each. It’s been suggested that the p-orbitals look like peanuts if that helps you to remember their shape.

7. The d-orbitals d xy d xz d yz Even though the d-orbitals look like two p-orbitals, it is important to remember that each orbital can hold a maximum of 2 electrons regardless of how many lobes it has. d x 2 -y 2 dzdz 2

8. The freaky (or flowery) f-orbitals

9. And Electron Configurations Orbital Diagrams

10. H: 1 electron, 1s 1 Electron configuration Electrons behave as though they are spinning on their axis. A half arrow is used to indicate if the direction of the spin is up ( ) or down ( ).

11. He: 2 electrons, 1s 2 Pauli Exclusion Principle: Each orbital can contain 2 electrons ONLY if the electron spins are in opposite directions. Pauli Exclusion Principle: Each orbital can contain 2 electrons ONLY if the electron spins are in opposite directions.

12. Li: 3 electrons, 1s 2 2s 1 Auf bau principle: the electrons fill the orbitals starting with the lowest energy level and working their way up the energy ‘ladder’

13. Be: 4 electrons, 1s 2 2s 2

14. B: 5 electrons, 1s 2 2s 2 2p 1

15. C: 6 electrons, 1s 2 2s 2 2p 2 Hund’s Rule: all sublevel orbitals of the same energy must be filled with a single electron before the electrons can begin to pair up.

16. Sc: 21 electrons, 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 1 Total electrons 241012182021  complete configuration Shorthand notation:  noble gas core configuration 4s 2 3d 1 [Ar]

17. n 1 2 3 4 5 6 7 n -1 n -2 d-block metals f-block metals s-block metals p-block elements

19. Hydrogen Helium 1 1 1 2

20. LithiumBoron Beryllium 2 1 1 2 1 2 1 2 2 2 2 2 2 1

21. Lithium Beryllium 2 1 1 2 1 2 2 2 Boron 1 2 2 2 2 1

22. 1 2 2 2 2 1 Carbon 1 2 2 2 2 2 Nitrogen 1 2 2 2 2 3 Oxygen 1 2 2 2 2 4

23. 1 2 2 2 2 4 Fluorine 1 2 2 2 2 5 Neon 1 2 2 2 2 6

24. Chlorine (Cl) Nickel (Ni) 1 2 2 2 2 6 3 2 3 5 1 2 2 2 2 6 3 2 3 6 4 2 3 8 Rubidium (Rb) 1 2 2 2 2 6 3 2 3 6 4 2 3 10 4 6 5 1

25. 1s 1 1s 2 2s 1 2s 2 2p 1 2p 2 2p 3 2p 4 2p 5 2p 6 3s 1 3s 2 3p 1 3p 6 4s 1 4s 2 3d 1 3d 10 4p 1 4p 6 4d 1 4d 10 5d 1 We’ll look at the f-block tomorrow 4f 14 5f 14 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4 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 8

26. Chemical reactivity depends upon the number of electrons in the highest energy level (the largest n). Electron dot structures show only the outermost electrons so that reactivity can be easily predicted. The outermost electrons are also called the valence electrons. Electron Dot Structures Rules to Drawing Electron Dot Structures 1.Electrons 1-4 are added singly. 2.Exception: If there only two electrons, they’re shown as a pair. 3.Electrons 5-8 are paired with the single electrons that are already there.

27. Xe Sr N Examples: 1. What is the electron configuration of strontium (Sr)? 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 The highest energy level is n=5 and there are 2 electrons in it. Therefore, Sr has 2 valence electrons. 2. What is the electron configuration of nitrogen (N)? 1s 2 2s 2 2p 3 The highest energy level is n=2 and there are 5 electrons in it. Therefore, N has 5 valence electrons. 3. What is the electron configuration of xenon (Xe)? 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 3p 6 5s 2 4d 10 5p 6 The highest energy level is n=5 and there are 8 electrons in it. Therefore, Xe has 8 valence electrons.

28. Excluding a few exceptions, how many valence electrons would all of the d-block and f-block elements have?

29. 1 234567 8 # Valence electrons