Ionic Compounds

• Chemical Bonds

  . There are three types of strong chemical bonds:

  - ionic bonds

  - covalent bonds

  - metallic bonds

  . Atoms that have gained or lost electrons are called ions

  . Ionic bonds occur between positive and negative ions
• Ionic Bonding

  . Ions are formed when atoms gain or lose electrons, giving them an overall charge

  . Ions have a complete outer shell of electrons (the same electron configuration as a noble gas)

  . Ionic bonding involves a transfer of electrons from metal atoms to non-metal atoms

  . The metal atoms lose electrons to become positively charged ions

  . The non-metal atoms gain electrons to become negatively charged ions

  . The ionic bond is a strong electrostatic force of attraction between the positive metal ion and the negative non-metal ion
• Key Point

  The arrangement of electrons in an atom can be described in terms of shells or energy levels. Electron configuration diagrams are a good example of using diagrams to represent information
• Properties of Ionic Compounds

  . Ionic compounds are giant structures of ions

  . They are held together by strong forces of attraction (electrostatic forces) that act in all directions between oppositely charged ions, i.e. ionic compounds are held together by strong ionic bonds

  . Ionic compounds:

  - have high melting and boiling points

  - do not conduct electricity when solid, because the ions cannot move

  - conduct electricity when molten or in solution, because the charged ions are free to move about and carry their charge
• Key Point

  An ionic bond is the attraction between oppositely charged ions
• Key Point

  Ionic compounds have high melting and boiling points because ionic bonds are very strong and it requires lots of energy to overcome them
• Key Point

  . Group 1 elements form ions with a 1+ charge

  . Group 2 elements form ions with a 2+ charge

  . Group 7 elements form ions with a 1- charge

  . Group 6 elements form ions with a 2- charge