Organic Chemistry Lecture Notes

Introduction to Organic Chemistry

• Organic Chemistry: Focuses on organic compounds containing carbon atoms.
• Carbon Bonding: Typically forms four bonds. Other elements:
  • Hydrogen: 1 bond
  • Beryllium: 2 bonds
  • Boron: 3 bonds
  • Nitrogen: 3 bonds
  • Oxygen: 2 bonds
  • Halogens (Fluorine, Chlorine, Bromine, Iodine): 1 bond

Lewis Structures

• Importance: Helps in understanding molecule structure.
• Structure Examples:
  • Water (H2O):
    • Oxygen forms 2 bonds, has 2 lone pairs.
    • Hydrogen forms 1 bond.
  • Methyl Fluoride (CH3F):
    • Carbon: 4 bonds
    • Fluorine: 3 lone pairs, completes octet.

Types of Bonds

• Polar Bonds:
  • Polar Covalent Bond: Uneven electron sharing, e.g., C-F.
  • Hydrogen Bond: H attached to N, O, or F.
• Non-Polar Bonds:
  • Example: C-H bond, electronegativity difference < 0.5.

Difference Between Covalent and Ionic Bonds

• Covalent Bonds: Electrons are shared.
• Ionic Bonds: Electrons are transferred.

Alkanes and Alkenes

• Alkanes: Saturated, formula CnH2n+2.
  • Methane, Ethane, Propane, Butane, etc.
• Alkenes: Unsaturated, contains double bonds.
  • Example: Ethene (C2H4).

Bond Length and Strength

• Bond Lengths:
  • Single > Double > Triple
• Bond Strength:
  • Triple > Double > Single

Sigma and Pi Bonds

• Single bond = 1 sigma bond.
• Double bond = 1 sigma + 1 pi bond.
• Triple bond = 1 sigma + 2 pi bonds.

Hybridization

• Determination: Count atoms and lone pairs around the carbon.
  • sp3: 4 groups
  • sp2: 3 groups
  • sp: 2 groups

Formal Charge Calculation

• Formula: Valence electrons - (Bonds + Dots)
• Examples covered for carbon and sulfur.

Functional Groups

• Alcohols: OH group, e.g., Ethanol.
• Aldehydes: Carbonyl group at end, e.g., Ethanal.
• Ketones: Carbonyl group in middle, e.g., Propanone.
• Esters: RCOOR', e.g., Methyl Ethanoate.
• Carboxylic Acids: COOH group, e.g., Pentanoic Acid.

Expanded Structures

• Tips on how to draw expanded structures from condensed formulas.
• Examples given with detailed walkthroughs for clarity.