Organic Chemistry Lecture Notes

Introduction

• Purpose: Experiment on reverse psychology by advising not to watch the video.
• Request: Comment on why they chose to watch.

Basics of Organic Chemistry

Understanding Lewis Structures

• Lewis Structures: Diagrams showing the bonds between atoms of a molecule and lone pairs of electrons.
• Periodic Table Review:
  • Group 1 (e.g., Hydrogen): 1 valence electron, forms 1 bond.
  • Group 2 (e.g., Beryllium): 2 valence electrons, forms 2 bonds.
  • Group 3A (e.g., Boron): 3 valence electrons, forms 3 bonds.
  • Carbon: 4 valence electrons, forms 4 bonds.
  • Nitrogen: 5 valence electrons, forms 3 bonds in neutral state.
  • Oxygen: 6 valence electrons, forms 2 bonds.
  • Fluorine: 7 valence electrons, forms 1 bond; trend similar for other halogens.
  • Sulfur, Selenium: Forms 2 bonds.
  • Phosphorus: Forms 3 bonds.

Drawing Lewis Structures

• Methane (CH4): Carbon forms 4 bonds with hydrogen.
• Ethane (C2H6): Each carbon forms 4 bonds; carbon-carbon single bond.
• Propane (C3H8): Similar pattern; no double/triple bonds (saturated).

Alkenes and Alkynes

• Ethene (C2H4): Double bond between carbons; unsaturated.
• Ethyne (C2H2): Triple bond; known as alkyne.

Nomenclature and Naming

Common Names for Alkanes

• Methane (CH4): 1 carbon.
• Ethane (C2H6): 2 carbons.
• Propane (C3H8): 3 carbons.
• Butane (C4H10): 4 carbons.
• Pentane (C5H12): 5 carbons.
• Hexane (C6H14): 6 carbons.
• Heptane (C7H16): 7 carbons.
• Octane (C8H18): 8 carbons.
• Nonane (C9H20): 9 carbons.
• Decane (C10H22): 10 carbons.

Alcohols and Ethers

• Methanol (CH3OH): Alcohol with one carbon.
• Ethanol: Derived from ethane with OH group.
• Ethers: R-O-R'; named by groups attached to oxygen (e.g., dimethyl ether).

Ketones, Aldehydes, and Carboxylic Acids

• Ketones: Carbonyl group in the middle (e.g., 2-butanone).
• Aldehydes: Carbonyl group at the end (e.g., ethanal).
• Carboxylic Acids (R-COOH): Weak acids (e.g., propanoic acid).

Esters and Amines

• Esters: Derived from carboxylic acids (e.g., methyl ethanoate).
• Amines: R-NH2; named as alkylamine (e.g., ethylamine).

Functional Groups

• Amides: Carbonyl group attached to NH2.
• Nitriles, Acid Chlorides, Benzene Rings: Other important functional groups.

Resonance Structures

• Concept: Movement of electrons, not atoms.
• Resonance Stability: Major contributor has less separation of charge.

Formal Charge Calculation

• Formula: Number of valence electrons - (number of bonds + dots).
• Examples: Calculation for oxygen and nitrogen in various states.

Resonance and Hybrid Structures

• Drawing Resonance Structures: Use curved arrows for electron movement.
• Examples: Acetate ion and amide.

Naming Alkanes with IUPAC Nomenclature

• General Approach: Identify longest chain and substituents.
• Examples: 3-methylhexane, 3,4-dimethylheptane.

Conclusion

• Further Resources: Recommend checking additional resources for deeper understanding.