Organic Chemistry Lecture Notes

Introduction

• Focus on organic compounds containing carbon atoms.
• Carbon typically forms four bonds.
• Importance of understanding bonding preferences of other elements.

Bonding Preferences for Common Elements

• Hydrogen: 1 bond
• Beryllium: 2 bonds
• Boron: 3 bonds
• Carbon: 4 bonds
• Nitrogen: 3 bonds
• Oxygen: 2 bonds
• Halogens (Fluorine, Chlorine, Bromine, Iodine): 1 bond
  • Exception: Can form 7 bonds (not covered in this lecture)

Lewis Structures

• Example: Water (H2O)
  • Oxygen: 2 bonds, 2 lone pairs
  • Importance: Determines molecule stability and arrangement
• Hydrogen Bonds: Occur with N, O, or F
• Methyl Fluoride: Polar bond due to difference in electronegativity

Types of Covalent Bonds

• Nonpolar Covalent Bonds: Electrons shared equally (e.g., H2)
• Polar Covalent Bonds: Electrons shared unequally (e.g., H-F)

Ionic Bonds

• Formation: Transfer of electrons
• Example: NaCl (sodium donates electron to chlorine)
• Cation: Positively charged ion (e.g., Na+)
• Anion: Negatively charged ion (e.g., Cl-)

Alkanes and Their Naming

• Methane (CH4): 1 carbon
• Ethane (C2H6): 2 carbons
• Propane (C3H8): 3 carbons
• Butane (C4H10): 4 carbons
• General Formula: CnH2n+2

Drawing Lewis Structures for Alkenes and Alkynes

• Ethene (C2H4): Double bond
• Ethyne (C2H2): Triple bond
• Alkanes: Saturated compounds
• Alkenes/Alkynes: Unsaturated compounds

Bond Length and Strength

• Single Bond: Longest and weakest
• Triple Bond: Shortest and strongest
• Sigma Bonds: Stronger than pi bonds

Hybridization

• Determining Hybridization: Count atoms attached and lone pairs
  • Example: CH4 (sp3), C2H4 (sp2), C2H2 (sp)
• Bond Hybridization Example: CH bond in methane is sp3-s

Sigma and Pi Bonds in Molecules

• Counting sigma (σ) and pi (π) bonds
• Example: Structure with 6 σ bonds and 2 π bonds

Calculating Formal Charge

• Formula: Valence Electrons - (Bonds + Dots)
• Example: Sulfur (-1) in certain structures

Functional Groups in Organic Compounds

• Alcohols: Contain OH group (e.g., Ethanol)
• Aldehydes: CHO group (e.g., Ethanal)
• Ketones: Carbonyl group in middle (e.g., Propanone)
• Esters: Contain COO group
• Carboxylic Acids: COOH group (e.g., Pentanoic acid)

Expanding Condensed Structures

• Example structures and functional group identification
• Common patterns in drawing organic compounds

Additional Resources

• Mention of additional resources and playlists for further study on organic chemistry topics.