8.1 Molecular Compounds

• Molecular compounds

  Tend to have lower melting points than ionic compounds
• Molecule of water

  • H₂O
• Molecular compounds


  Neutral group of atoms joined by covalent bonds
• Covalent molecule of carbon dioxide

  • CO₂
• Shared electrons

  Molecular compounds are held together by sharing of elections
• Ball-and-stick molecular model


  A model that shows the atoms and bonds in a molecule
• Structural formula


  Representation of a molecule showing the arrangement of atoms and how they are connected
• Molecule of ethane


  • C₂H₆
• Molecular formula


  Shows how many atoms of each element a molecule contains
• Covalent bonds are formed by the sharing of electrons between atoms
• Space-filling molecular model

  A model that shows the true shapes of molecules
• Covalent molecule of ammonia

  • NH₃
• Covalent bonds

  An attraction of + and - ions
• Covalent (2)

  Double covalent bond