Covalent structures: Bonding structure and the properties of matter: Chemistry: GCSE (9:1)

• Covalent bond


  A shared pair of electrons

  
• Molecule


  A group of two or more atoms held together by covalent bonds

  
• Examples of simple molecular substances


  CO2, H2O, NH3
• Polymer


  A long molecule consisting of many similar or identical monomers linked together.

  
• Examples of giant covalent structures

  Diamond, graphite, silicon dioxide

  
• Limitations of dot and cross diagrams

  Do not show the 3D shape of a molecule

  
• Limitations of ball and stick diagrams

  Bonds appear longer than they really are

  
• Molecular formula


  A chemical formula of a shows the kinds and numbers of atoms present in a molecule

  
• Empirical formula

  A chemical formula showing the ratio of elements in a compound

  
• Giant covalent structure


  A huge 3D network of covalently bonded atoms

  
• Monomer


  A small compound whose molecules can join together to form polymers

  
• Double covalent bond


  A bond in which two atoms share two pairs of electrons

  
• Triple covalent bond

  A bond formed by sharing three pairs of electrons