covalent bonding

• definition?

  strong electrostatic forces of attraction between a shared pair of electrons and a positive nuclei
• simple molecular structure?

  low melting point = weak intermolecular forces of attraction between molecules = less energy needed to overcome forces

  can't conduct electricity = all bonds made = no free electron to flow and carry a charge

  usually insoluble in water

  liquid/gas at room temp = enough energy to overcome forces
• as the relative formula mass increases = the melting and boiling point increases?


  larger molecules have more forces of attraction = more energy needed to overcome and break the bonds
• giant covalent structures?

  • high boiling and melting point = lots of strong covalent bonds = lots of energy needed to overcome and break the bonds
• diamond?

  • made of carbon
  • doesnt conduct electricity = no free electron to carry a charge
  • has a high melting point = a giant covalent structure = lots of strong covalent bonds = lots of energy needed to overcome and break the bonds
  • high density and is hard
• graphite?

  • a giant lattice - three covalent bonds each
  • conducts electricity = one free electron to move freely and carry a charge
  • malleable = weak forces of attraction between layers = layers slide across easily = soft substance
• graphene?

  = single layer of graphite

  • transparent = one atom thick
  • better conductor of electricity than graphite
• giant lattice is diamond, graphite and silicon dioxide
• simple covalent has low m.p as it takes little energy to overcome the weak intermolecular forces of attraction
• giant lattice has a very high m.p as lots of energy is need to break the strong bonds in a lattice
• fullerene (C60) is hollow = can put metal inside of the tube