structure and properties

• molecule = two or more atoms that are covalently bonded
• simple molecular substances have low melting and boiling points because the forces that hold the molecules together are weak and easily broken
• the larger the molecule, the higher the melting and boiling point are
• molecules don't conduct electricity or heat
• molecules are poor conductors of electricity because there are no charged particles or free electrons to move and carry heat
• molecule diagram

  
• does not conduct electricity = no charged particles
• As the particles are heated they gain electrons. This makes them vibrate more and more until they have enough energy to escape from the lattice structure
• simple molecular substances have low melting points and boiling points because the forces that hold the molecules together are weak and easily broken
• the larger the molecule, the higher the mp and bp
• simple molecular structures do not conduct electricity or heat
• when they are gases, most nonmetals form simple molecules where two atoms are joined together
• simple covalent molecules (gases)

  • small, few atoms bonded together
  • strong covalent bonds between atoms, weak intermolecular forces
  • can't conduct electricity, there are no delocalised electrons
  • has a low boiling and melting point doesn't take a lot of energy to break bonds