Types of formula

• Structural formula

  • Shows all the atoms and bonds in a molecule

  
• Molecular formula

  • Number of each element in the molecule (does not indicate bonds or structure)
  • e.g: CO₂ / C₄H₈
• Empirical formula

  • The simplest whole number ratio of the atoms in a molecule
  • e.g: C₄H₈ -> CH₂
• Skeletal formula

  • Shows all of the bonds in a molecule, and any elements which are not carbon or hydrogen

  
• Condensed formula

  • Number of each element in a molecule, written out taking into account structure
  • Side chains are in brackets
  • If something is repeated (likely CH₃) it will be in brackets with a small number on the outside - (CH₃)₂