metallic bonding

• Metallic bonding:


  This type of bonding occurs between METALS.

  
• Metallic bonding:

  The outer shell electrons are DELOCALISED & 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 & the SEA OF DELOCALISED ELECTRONS are the METALLIC BONDS, which hold the structure together.

  
• PROPERTIES OF METALS:

  • High melting points
  • good conductivity of electricity & heat
  • malleable
  • high strength
• METALS have HIGH MELTING POINTS:

  As there're STRONG ELECTROSTATIC FORCES of attraction between positive metal ions & the SEA OF DELOCALISED ELECTRONS.

  • This requires a LARGE AMOUNT OF ENERGY to overcome.
  • Generally solid at room temperature.
• Metals are GOOD CONDUCTIVITY OF ELECTRICITY:


  As the DELOCALISED ELECTRONS in the metal CARRY AN ELECTRICAL CHARGE through its structure.
• metals are GOOD CONDUCTIVITY OF HEAT / thermal energy:


  As delocalised electrons from outer shell are free to move, so energy is TRANSFERRED through structure.
• Pure Metals are MALLEABLE:


  They can be BENT or SHAPED without breaking, as metals have such a regular structure, so the layers of atoms can slide over one another.

  
• PURE metals are too soft for many uses, so they're turned to alloys:

  • As they have a higher strength
  • because the atoms / ions of the different elements have different sizes that DISTORT the regular layered structure of pure metals.
  • This makes it more difficult for them to SLIDE over each other.

  
• ALLOYS:


  A metal combined with one or more other elements.
• Metallic bonding:

  • A solid metal consists of a giant structure of atoms that are arranged in a regular pattern.
  • Because of this they give up their outer shell electrons & share them with all the other atoms in the metal.
  • Meaning the atoms will all become positive ions because they’ve lost negative electrons.
  • Now those electrons are now free to move about, they’re delocalised electrons.
  • So there will now be loads of strong electrostatic attraction between the positive ions & the negative electrons.
  • These forces of attraction holds everything together in a regular structure.

  
• Steel:


  An alloy that is made mostly of iron (generally >99% iron), but with a small amount of other elements (most often carbon) added to it.