chemistry 2.1

• Intramolecular forces

  Responsible for the formation of all solid materials - this occurs at an atom or ion microscopic level

  
• Types of intramolecular forces

  • Metallic
  • Ionic
  • Covalent (molecular or continuous)

  
• Types of solid materials

  • Metals
  • Ionic Compounds
  • Covalent Molecules
  • Covalent Networks
• Covalent molecules and networks

  • Held together by covalent bonds but are considered two distinct groups due to their unique structures and properties
• Metallic solids


  Formed by interactions of metal atoms
• Lattice structure of metals

  • Combination of uniform distribution of atomic nuclei elements and a sea of delocalised electrons
• Ionic solids

  Composed of interacting atoms of metallic and non metallic elements
• Geometrical structure of ionic lattice

  • Results from electrostatic attraction between positive cations and negative anions which interact in a fixed ratio
• Covalent molecular solids

  Composed of discrete molecules which interact to form solid materials
• Covalent bonding

  Occurs when two non-metallic atoms share valence electrons pairs
• Covalent network solids


  Composed of interacting atoms of non-metallic elements
• Network lattice of covalent network solids

  • Results from each atom forming covalent bonds with the neighboring atom at each valence electron site
• Melting point


  Characteristic of all materials, dependent on strength of attraction between the particles present
• Melting of solids


  Heat energy applied vibrates particles, disrupting organisation and breaking bonds causing melting
• Electrical conductivity


  Physical property that can be used to classify the intramolecular force present in a material, involves the flow (current) of free electrons or ions through a solid, molten or aqueous medium
• Electrical conductivity of materials

  • Delocalised electrons within a metallic lattice allow the flow of charge
  • Ions in solid ionic materials are locked into a fixed position - cannot carry charge
  • Covalent molecular solids and network solids do not exhibit electrical conductivity in either pure form or when dissolved in water