Covalent bonding

Cards (11)

  • In a covalent bond, the shared electrons are attracted to the nuclei of both atoms, creating a strong bond.
    • Occurs in most non-metallic elements and in compounds of nonmetals
    • Strong bonds between atoms that are covalently bonded are the result of electrostatic attraction between the positive nuclei of the atoms and the pairs of negative electrons that are shared between them
    • Substances that consists of small molecules:
    • Are usually gases or liquids that have low boiling and melting points
    • Have weak intermolecular forces between the molecules
    • These are broken in boiling melting, not the covalent bonds
    • Don't conduct electricity
    • As the small molecules do not have an overall electric charge
    • Intermolecular forces increase with the size of the molecules
    • The larger the molecules, the higher the melting and boiling points
    • Substances that consist of giant covalent structure are all solids with very high melting points
    • All the atoms are linked to other atoms by strong covalent bonds
    • Bonds must be overcome to melt or boil these substances
  • Diamond
    • Each carbon covalently joined to 4 other carbons
    • Very hard
    • Very high melting point
    • Does not conduct electricity
  • Graphite
    • Each carbon is covalently bonded to 3 other carbons
    • Forming layers of hexagonal rings
    • Weak intermolecular forces between the layers
    • No covalent bonds between the layers
    • = soft and slippery
    • One electron from each carbon is delocalized
    • Conduct electricity
  • Graphene
    • Single layer of graphite
    • Has properties that make it useful in electronics and composites
  • Fullerenes
    • Molecules of carbon atom with hollow shapes
    • Based on hexagonal rings of carbon atoms
    • May also contain rings with 5 or 7 carbon atoms
    • First fullerene to be discovered was Buckminsterfullerene (C60)
    • Spherical shape
  • Carbon nanotubes
    • Cylindrical fullerenes with very high length to diameter ratios
    • There properties make them useful for nanotechnology, electronics and materials
     
    • Covalent compounds don't conduct electricity except graphite and graphene