Cemistry Revision

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  • Created by: Christina
  • Created on: 14-01-11 09:59

Structures and Properties

 

Structures and Propertres

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Ionic Compound

  • Conisists of a giant structure of ions arranged in a lttice
  • Attractive electrostatic forces between the oppositely charged ions act in all directions and are very strong
  • These forces holds the ions in the lattice togehter very tightly
  • It takes alot of energy to break the lattice apart meanining that ionic compounds have very high melting and boiling points
  • If the lattice has been broken, the ions are free to move and the ionic solid becomes a liquid - the ions are free to move through the molten liquid
  • A solid ionic compound can't conduct electricity because each ion is held in a fixed position in the lattice and are unable to move around - they can only vibrate
  • Many ionic compunds can dissolve in water
  • when this happens the lattice is split up by the water molecules
  • When the ions are free to move around in an ionic compoud it is able to conduct electricity
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Ionic Compounds

Basically....

Ionic Solid: Ions fixed in lattice - doesn't conduct electricity

Molten Ionic Compound:High temperature provides energy to overcome strong attractive foreces between ions, ions are free to move so will conduct electricity

Ionic compound in solution: Water molecules separate ions from the lattice, ions are free to move so will conduct electricity

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Simple Molecules

  • Covalent molecules are non-metals which react to form compounds by sharing electrons in their outer shell
  • Substances made from covalent bonding, have low melting and boiling points
  • This means that many simple molecules are liquid or gas at room temperature
  • Covalent bonds are very strong
  • Atoms within each molecule are held very tightly together
  • Each molecule tens
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Comments

Muntaha

Dude, this is good but it doesn't get into my head and my exam is this monday. :'(

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