2. Chapter 1 Introduction and Review Organic Chemistry, 6 th Edition L. G. Wade, Jr.

3. Chapter 12 Definitions Old: “derived from living organisms” New: “chemistry of carbon compounds” From inorganic to organic, Wöhler, 1828

4. Chapter 13 Atomic Structure Atoms: protons, neutrons, and electrons. The number of protons determines the identity of the element. Some atoms of the same element have a different number of neutrons. These are called isotopes. Example: 12 C, 13 C, and 14 C

5. Chapter 14 Electronic Structure Electrons: outside the nucleus, in orbitals. Electrons have wave properties. Electron density is the probability of finding the electron in a particular part of an orbital. Orbitals are grouped into “shells,” at different distances from the nucleus.

6. Chapter 15 First Electron Shell The 1s orbital holds two electrons. Spherical shape

7. Chapter 16 Second Electron Shell Three p orbitals P-orbital (dumbell shaped) S-Orbital (spherical) Second shell (4 orbitals) holds total of 8 electrons

8. Chapter 17 Electronic Configurations Aufbau principle: Place electrons in lowest energy orbital first. Hund’s rule: Equal energy orbitals are half- filled, then filled. 6 C: 1s 2 2s 2 2p 2  

9. Chapter 18 Electronic Configurations =>

10. Chapter 19 Bond Formation Ionic bonding: electrons are transferred. Covalent bonding: electron pair is shared.

11. Chapter 110 Lewis Structures Bonding electrons represented by a dash line or a pair of electron Nonbonding electrons or lone pairs are shown Satisfy the octet rule!

12. Chapter 111 Multiple Bonding =>

13. Chapter 112 Dipole Moment Amount of electrical charge x bond length.

14. Chapter 113 Electronegativity and Bond Polarity Greater  EN means greater polarity =>

15. Chapter 114 Calculating Formal Charge For each atom in a valid Lewis structure: Count the number of valence electrons Subtract all its nonbonding electrons Subtract half of its bonding electrons F.C = # valence e – (non-bonding e + 1/2(bonding e)

16. Chapter 115 Ionic Structures X => If the  EN is greater than 2.5, the bond is a ionic bond.

17. Chapter 116 Resonance Only electrons can be moved (usually lone pairs or pi electrons). Nuclei positions and bond angles remain the same. The number of unpaired electrons remains the same. Resonance causes a delocalization of electrical charge.

18. Chapter 117 Resonance Example The real structure is a resonance hybrid. All the bond lengths are the same. Each oxygen has a -1/3 electrical charge.

19. Chapter 118 Major Resonance Form or Major Contributor has as many octets as possible. has as many bonds as possible. has the negative charge on the most electronegative atom. has as little charge separation as possible.

20. Chapter 119 Resonance Hybrid major contributor minor contributor, carbon does not have octet =>

21. Chapter 120 Chemical Formulas Full structural formula (no lone pairs shown) Line-angle formula Condensed structural formula Molecular formula Empirical formula CH 3 COOH C2H4O2C2H4O2 CH 2 O

22. Chapter 121 Calculating Empirical Formulas Given % composition for each element, assume 100 grams. Convert the grams of each element to moles. Divide by the smallest moles to get ratio. Molecular formula may be a multiple of the empirical formula.

23. Chapter 122 Sample Problem An unknown compound has the following composition: 40.0% C, 6.67% H, and 53.3% O. Find the empirical formula. 3.33 = 1 = 1.98 = 2 Empirical Formula: CH 2 O

24. Chapter 123 Arrhenius Acids and Bases Acids dissociate in water to give H 3 O + ions. Bases dissociate in water to give OH - ions. K w = [H 3 O + ][OH - ] = 1.0 x 10 -14 at 24°C pH = -log [H 3 O + ] Strong acids and bases are 100% dissociated.

25. Chapter 124 BrØnsted-Lowry Acids and Bases Acid: donates a proton. Base: accepts a proton. Conjugate acid-base pairs. acid conjugate base conjugate acid =>

26. Chapter 125 Acid and Base Strength Acid dissociation constant, K a Base dissociation constant, K b For conjugate pairs, (K a )(K b ) = K w Spontaneous acid-base reactions proceed from stronger to weaker. pK a 4.74pK b 3.36pK b 9.26pK a 10.64

27. Chapter 126 Structural Effects on Acidity Electronegativity Size Resonance stabilization of conjugate base

28. Chapter 127 Electronegativity As the bond to H becomes more polarized, H becomes more positive and the bond is easier to break. =>

29. Chapter 128 Size As size increases, the H is more loosely held and the bond is easier to break. A larger size also stabilizes the anion.

30. Chapter 129 Resonance Delocalization of electron pairs. More resonance structures usually mean greater stabilization. Acidity:

31. Chapter 130 Lewis Acids and Bases Acids accept electron pairs = electrophile Bases donate electron pairs = nucleophile =>

32. Chapter 131 End of Chapter 1