Bonding

• Types of chemical bonds

  • Ionic
  • Covalent
  • Metallic
• Ionic bonding


  Particles are oppositely charged ions, occurs in compounds formed from metals and non-metals
• Covalent bonding


  Particles are atoms which share pairs of electrons, occurs in non-metallic compounds and non-metallic elements
• Metallic bonding


  Particles are atoms which share delocalised electrons, occurs in metallic elements and alloys
• Ionic bonding


  Metal atoms lose electrons to become positively charged ions
• Ionic compounds


  • Giant structure of oppositely charged ions held together by strong electrostatic forces of attraction
• Covalent bonding


  Atoms share one or more pairs of electrons
• Covalent compounds


  • Polymers, diamond, silicon dioxide
• Metallic bonding


  • Consists of positive ions and delocalised electrons
• In ionic compounds, when melted or dissolved in water, they conduct electricity because the ions are free to move and carry current
• Polymers


  • Have very large molecules, held together by strong covalent bonds
• Giant covalent structures


  • Diamond and graphite
• Diamond


  Each carbon atom is joined to 4 others covalently, very hard and high melting point, doesn't conduct electricity
• Graphite


  Each carbon atom is connected to 3 others, forms layers of hexagon rings which have no covalent bonds between layers, soft and slippery due to weak intermolecular forces, has delocalised electrons
• Graphene


  • Single layer of graphite, very strong due to strong forces, also elastic as planes of atoms can slide relatively easily without bonds breaking
• Fullerenes


  Molecules of carbon atoms with hollow shapes
• Fullerenes


  • Buckminster Fullerene (C60) which has a spherical shape
• Fullerenes


  • Low melting point, soft and slippery
• Uses of fullerenes

  • Medicine, storage, electronics
• Carbon nanotubes

  • Cylindrical fullerenes, properties make them useful for nanotechnology, electronics
• Uses of carbon nanotubes


  • Lubricants, drug delivery, tennis rackets