metallic bonding

• Metallic Bonding 

  • This type of bonding occurs between METALS.
  • The outer shell electrons are DELOCALISED and free to move. This creates a SEA OF DELOCALISED ELECTRONS.
  • Within the sea of electrons, there are POSITIVE METAL IONS which are arranged in a REGULAR PATTERN in a GIANT STRUCTURE.
  • The ELECTROSTATIC ATTRACTION between the POSITIVE METAL IONS and the SEA OF DELOCALISED ELECTRONS are the METALLIC BONDS which hold the structure together.
• HIGH MELTING POINTS

  • There are STRONG ELECTROSTATIC FORCES of attraction between positive metal ions and the SEA OF DELOCALISED ELECTRONS.
  • This requires a LARGE AMOUNT OF ENERGY to overcome.
  • This means their melting points are high and metals are generally SOLID at ROOM TEMPERATURE.
• GOOD CONDUCTIVITY OF ELECTRICITY

  Metals are good conductors of electricity because the DELOCALISED ELECTRONS in the metal CARRY AN ELECTRICAL CHARGE through its structure.
• GOOD CONDUCTIVITY OF HEAT

  Metals are good conductors of THERMAL ENERGY because energy is TRANSFERRED well by the delocalised electrons.
• MALLEABLE:

  This means they can be BENT or SHAPED without breaking, due to the LAYERS of atoms that can SLIDE over each other.

   

  PURE metals are too soft for many uses, so are turned into ALLOYS which are more useful.

  ALLOYS are MIXTURES of different metals.

  ALLOYS are harder materials than PURE metals because the different sizes of atoms DISTORT the layers of atoms.

  This makes it more difficult for them to SLIDE over each other.
• changing matter: