ionic/covalent structures

• what are the 3 types of bond?


  metallic, ionic, covalent
• what happens to electrons when an ionic bond is formed?

  transferred
• what type of elements will form ionic bonds?

  metals and non metals
• what is the charge of the ions formed from elements in groups 1,2,6 and 7?

  +1, +2, -2, -1
• describe the structure and bonding in an ionic compound

  giant ionic lattice, strong ionic bonds between oppositely charged ions
• explain why ionic compounds have high melting/boiling points

  a lot of energy is needed to break many strong ionic bonds between oppositely charged ions
• explain why ionic compounds conduct electricity when molten or dissolved


  ions are free to move and carry charge
• what happens to electrons when a covalent bond is formed?

  shared
• describe the structure of diamond

  giant covalent structure made of carbon atoms bonded to four other carbon atoms by covalent bonds
• what type of elements will form covalent bonds?

  non metals
• explain why diamond doesn't conduct electricity

  no delocalised electrons to carry charge
• explain why diamond and silicon dioxide have high melting points

  a lot of energy is needed to break the strong covalent bonds between atoms
• describe the structure of graphite

  giant covalent structure made of carbon atoms each bonded to 3 other carbon atoms to form hexagonal rings in layers, weak forces between layer, delocalised electrons
• explain why graphite conducts electricity

  delocalised electrons carry a charge through the structure
• explain why graphite can act as a lubricant

  layers are able to slide over each other easily
• explain why small molecules have low melting points

  weak intermolecular forces require little energy to overcome
• what is a polymer?

  lots of monomers that have joined together in a chain to form a large molecule
• why do larger molecules (like polymers) have higher melting points?

  the bigger the molecule, the stronger the intermolecular forces, the more energy required to break the,
• what is graphene?

  a single layer of graphite
• what is a fullerene?

  a single layer of grapheme folded in a specific shape (sphere, tube etc.)
• what are nanotubes and what are they used for?

  cylindrical fullerenes used for electronic, nanotechnology and drug delivery