Organic Chemistry Introduction - Part One

Lecturer

• Melissa Marabou

Key Element: Carbon

• Most important in organic chemistry
• Carbon has 4 valence electrons → can form 4 bonds

Ways to Represent a Molecule

1. Molecular Formula
2. Structural Formula
   • Similar to Lewis structure
3. Condensed Structural Formula
   • Derived from structural formula
   • Example process:
     • First carbon (left): 3 hydrogens → CH3
     • Middle carbon: 2 hydrogens → CH2
     • Last carbon (right): 3 hydrogens → CH3
4. Skeletal Formula (Line Diagram)
   • Points represent carbons, hydrogens not shown
   • Knowing carbon forms 4 bonds is crucial
   • Drawing Process Example:
     • Each point is a carbon
     • Fill in missing bonds with hydrogens:
       • Carbon w/1 bond → needs 3 hydrogens
       • Carbon w/2 bonds → needs 2 hydrogens
       • Carbon w/3 bonds → needs 1 hydrogen
   • Trick: Count to one less when drawing lines to get correct number of carbons

Example Question

• Structural formula: 4 carbons, 10 hydrogens
• Draw condensed structural formula and skeletal formula

Hydrocarbons

• Only contain hydrogen and carbon
• Types based on carbon bond types:
  1. Alkanes: single bonds only
  2. Alkenes: at least one double bond
  3. Alkynes: at least one triple bond
• Naming suffixes:
  • “-ane”: Alkane
  • “-ene”: Alkene
  • “-yne”: Alkyne

Longest Carbon Chain and Substituents

• Longest chain = main body
• Substituents = arms/legs
• Alkyl Groups (substituents made of C & H):
  • Derived from alkanes missing one hydrogen
  • Examples:
    • Methyl: 1 carbon
    • Ethyl: 2 carbons
    • Propyl: 3 carbons
    • Butyl: 4 carbons

Preview of Part Two

• Focus on functional groups
• Stay determined!