1. Electron Configurations

2. Quantum Theory Electrons are found in orbitals Defined by quantum numbers n, l and m. Like seats in a theatre organized in section, row, seat number

3. Principal Quantum Number (n) Values from 1-7 The larger the value, the further the orbital is from the nucleus

4. Principal Quantum Number (n) 12345671234567

5. The periodic table is organized into s, p, d and f blocks (as per diagram)

6. l quantum number Sublevel within an energy level where an electron can be found (similar to rows in a theatre) Ranges from 0 to n-1 (n = principal quantum #)

7. Example: If n=3, then l can be 0,1, or 2 Where: 0 = s block 1 = p block 2 = d block 3 = f block So, if n = 3 and l = 1, then it would correspond to a 3p electron l quantum number

8. m quantum number Sublevel where the electron is actually located (like your seat in a theatre) Can range from –l to +l If l = 0, m can only be 0  = an s orbital If l = 1, m can be -1, 0, or 1  = a p orbital There are 3 p orbitals per sublevel

9. Orbitals S orbital  holds up to 2 electrons P orbitals  each orbital holds 2 electrons for a total of 6 – P x = 2 – P y = 2 – P z = 2 D orbitals  5 orbitals holding 2 electrons each (10 total) F orbitals  7 orbitals holding 2 electrons each (14 total)

10. Summary of Principle Energy Levels, Sublevels & Orbitals Principle Energy Level (n) Sublevels (l, where l = 0 to n-1) Number of orbitals in the subshell Total number of orbitals in the energy level (n 2 ) Total number of electrons in the subshell 10 = 1s112 electrons 20 = 2s 1 = 2p 1313 48 electrons 30 = 3s 1 = 3p 2 = 3d 135135 918 electrons 40 = 4s 1 = 4p 2 = 4d 3 = 4f 13571357 1632 electrons

11. *Aufbau Principle* Electrons in an atom will fill the lowest energy level available first to remain stable

12. *Pauli Exclusion Principle* There can be 0, 1 or 2 electrons in an orbital If there are 2 electrons, they will spin in opposite directions

13. *Hund’s Rule* Electrons in the same sublevel will not pair up until all the orbits of a sublevel have been half filled

14. How to fill the orbitals Writing the electron configuration becomes easy with this!

15. Notation 1s 2  – Principal orbital = 1 – S block – 2 = # of electrons in the orbital – This represents the electron configuration of Helium

16. Examples Oxygen (element #8)

17. Magnesium (element #12) Examples

18. Copper (Element #29)

19. Short Hand notation Lithium (Li) Sodium (Na) Potassium (K)

20. Quiz NEXT Class! On everything in Atomic Structure up to this point UNIT TEST: Predicted for Tuesday October 4, 2011

21. Electronegativity Bond types: – Ionic  transfer of electrons from a metal to a non metal

22. – Covalent bond  sharing of electrons between non-metals

23. Lewis Dot Structures Show only the VALENCE (outer most) electrons Additional Examples

24. Water (H 2 O)

25. Non-Polar Covalent Bonds Only happens when two identical atoms bond (think of our diatomic) molecules!

26. Polar Covalent Bonds One of the atoms exerts a greater attraction than the other atom This means it pulls the electrons closer to the more electronegative atom

27. Electronegativity Increasing

28. Linus Pauling (1901-1994) Determined the relative “pull” or Attraction that each atom has higher the attraction, the stronger the hold the atom will have on the electron NOTE: the noble gases (group 18) do NOT have electronegativity values because they do not form bonds (full valence shell)

29. Examples: Water  H 2 O or HOH Electronegativity Values: – H  2.20 – O  3.50 (the Oxygen atom will pull harder on the electrons)

30. Examples: Non-polar covalent have a bond difference of 0.4 or less F 2  ∆E.N. = 4.10-4.10 = 0

31. Polar covalent bonds have a bond difference of 0.4-2.0 Example: hydrogen fluoride (HF) ∆E.N. = 4.10-2.20 = 1.90 Examples:

32. Ionic bonds have a bond difference greater than 2.0 (typically) Example: sodium chloride (NaCl) ∆E.N. = 2.83-1.01 = 1.82

33. Examples: Potassium fluoride (KF)

34. Chlorine (Cl 2 ) Examples:

35. Hydrochloric acid (HCl) Examples:

36. http://www.youtube.com/watch?v=QqjcCvzW www http://www.youtube.com/watch?v=QqjcCvzW www