Edexcel A Level Chemistry:复习笔记1.5.6 Giant Lattices

Giant Lattices

 

Ionic Lattices

  • The ions form a lattice structure which is an evenly distributed crystalline structure
  • Ions in a lattice are arranged in a regular repeating pattern so that positive charges cancel out negative charges
  • The attraction between the cations and anions is occurring in all directions
    • Each ion is attracted to all of the oppositely charged ions around it

     

  • Therefore the final lattice is overall electrically neutral

1.3-Chemical-Bonding-Ionic-Lattice

Ionic solids are arranged in lattice structures

 

 

Metallic Lattices 

  • Metals form giant metallic lattices in which the metal ions are surrounded by a ‘sea’ of delocalised electrons
  • The metal ions are often packed in hexagonal layers or in a cubic arrangement
  • This layered structure with the delocalised electrons gives a metal its key properties

1.4-States-of-Matter-Metallic-Lattice

Layers of copper ions (the delocalised electrons are not shown in the diagram)

 

Covalent lattices

  • Covalent bonds are bonds between nonmetals in which electrons are shared between the atoms
  • Covalent compounds can be arranged in simple molecular or giant molecular lattices
    • Simple molecular lattices: iodine, buckminsterfullerene (C60) and ice
    • Giant molecular: silicon(IV) oxide, graphite and diamond

     

1.4-States-of-Matter-Simple-Molecular-Lattice

 

Simple molecular lattices

 

1.4-States-of-Matter-Giant-Molecular-Lattice 

Giant molecular lattices

Exam Tip

Graphite, diamond and buckminsterfullerene are all allotropes of carbon; they are different structural forms of the same element (which is carbon).

 

 

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