bonding, structure and properties of matter

• when an atom loses or gains an electron, it forms an ion
• metals form positive ions
• non-metals form negative ions
• ionic bonding is the transferring of electrons
• ionic compounds have a regular lattice structure
• in a regular giant lattice, there are very strong electrostatic forces in all directions
• ionic compounds have hight melting and boiling points
• solid ionic compounds cant conduct electricity but once they are melted, they can
• covalent bonds: strong bonds and weak intermolecular forces
• polymers: large molecules made up of many small molecules joined together by covalent bonds
• polymer: repeating unit in brackets and 'n' outside
• giants covalent structures : macromolecules with very high melting and boiling points
• allotropes of carbon: graphite, diamond, graphene, fullerenes
• graphite: 2 layers of carbon atoms bonded together in a hexagonal lattice with no covalent bonds so they are free to move over eachother
• graphene: strong covalent bonds and can conduct electricity due to delocalised electrons
• fullerenes form spheres and tubes
• fullerene uses:

  delivering drugs

  industrial catalysts

  lubricants
• solids: strong forces of attraction

  vibrate in regular fixed positions

  keep a definite shape and volume
• liquids: weak force of attraction

  random arrangement so they are free to move past each other

  have a definite volume but not a shape

  random motions
• gas: very weak forces of attraction

  always fill a container

  move constantly in random directions
• nanoparticles: very high SA:V ratio, very small size, very high surface area, very high reactivity
• nanoparticles are used as catalysts, nanomedicine, tiny electric circuits, silver nanoparticles are used as antibacterials and cosmetics