1. October 5 th, 2015 What is the atomic mass of hafnium if, out of every 100 atoms, 5 have mass 176, 19 have mass 177, 27 have mass 178, 14 have mass 179, and 35 have mass 180.0? Electron Configurations: Chapter 5 sections 5.2 & 5.3

2. Why should I care? The number of electrons surrounding the nucleus determines all the chemical properties.

3. Electron Configuration: Shows the most stable arrangement of electrons around the nucleus. 1s 1 Energy Level Sublevel # of electrons

4. “S” Sublevel = Sphere Shaped 1 orbital Holds two (2) electrons

5. “P” Sublevel = Dumbbell Shaped Three (3) orbitals Holds two (2) electrons in each orbital (6 electrons total)

6. “D” Sublevel = Shaped like a cloverleaf Five (5) orbitals Holds two (2) electrons in each orbital (10 electrons total)

7. “F” Sublevel = Balloon Shaped Seven (7) orbitals Holds two (2) electrons in each orbital (14 electrons total)

8. SublevelOrbitalsElectrons s12 p36 d510 f714

9. H = __ 1s Electron Configuration Orbital Filling Diagram H = 1s 1 ATOMIC NUMBER

10. Pauli Exclusion Principle: 2 electrons in an orbital must have opposite spin

11. He = __ 1s Electron Configuration Orbital Filling Diagram He = 1s 2

12. 1 st Energy Level 2 nd Energy Level 3 rd Energy Level 4 th Energy Level 5 th Energy Level 6 th Energy Level s s s s s s p p p p p d d d d f f f Can Hold:

15. Li = __ __ 1s2s Electron Configuration Orbital Filling Diagram Li = 1s 2 2s 1

16. Aufbau Principle: Electrons are stable in the lowest energy level possible Aufbau comes from the German word aufbauprinzip which means building up.

17. Be= __ __ 1s2s Electron Configuration Orbital Filling Diagram Be= 1s 2 2s 2

18. B = __ __ __ __ __ 1s2s 2p Electron Configuration Orbital Filling Diagram B= 1s 2 2s 2 2p 1

19. Hund’s Rule: One electron enters each orbital until all have one of same spin, then pairs will be added.

20. C = __ __ __ __ __ 1s2s 2p Electron Configuration Orbital Filling Diagram C= 1s 2 2s 2 2p 2

21. N = __ __ __ __ __ 1s2s 2p Electron Configuration Orbital Filling Diagram N = 1s 2 2s 2 2p 3

22. O = __ __ __ __ __ 1s2s 2p Electron Configuration Orbital Filling Diagram O = 1s 2 2s 2 2p 4

23. F = __ __ __ __ __ 1s2s 2p Electron Configuration Orbital Filling Diagram F = 1s 2 2s 2 2p 5

24. Ne = __ __ __ __ __ 1s2s 2p Electron Configuration Orbital Filling Diagram Ne = 1s 2 2s 2 2p 6

25. Rule of Eight: An atom is most stable when it has 8 electrons in its outer shell, called an Octet

27. 1 2 3 4 5 6 7

28. 1 2 3 4 5 6 7 __ __ __ __ __ 3d

29. __ __ __ __ __ __ __ 4f 1 2 3 4 5 6 7

30. Assignment Complete Electron Configurations & Orbital Diagram practice (WS) Finish atomic history (WS) Book Readings are due Friday.