CIE A Level Chemistry复习笔记1.3.5 Ionic Bonding Examples

Ionic Bonding: Examples

Sodium chloride

  • Sodium is a Group 1 metal
    • It loses its outer electron to form a sodium ion with a +1 charge (Na+)
  • Chlorine is a Group 7 non-metal
    • It gains 1 electron to form a chloride ion with a -1 charge (Cl-)
  • The oppositely charged ions are attracted to each other by electrostatic forces to form NaCl (ionic bonds)
  • The final ionic solid is neutral in charge

1.3-Chemical-Bonding-Sodium-Chloride-Dot-Cross-Diagram

Dot and cross diagram to show the ionic bonding in sodium chloride

Magnesium oxide

  • Magnesium is a Group 2 metal
    • It loses its 2 outer electrons to form a magnesium ion with a +2 charge (Mg2+)
  • Oxygen is a Group 6 non-metal
    • It gains 2 electrons to form an oxide ion with a -2 charge (O2-)
  • The oppositely charged ions are attracted to each other to by electrostatic forces to form MgO (ionic bonds)
  • The final ionic solid is neutral in charge

1.3-Chemical-Bonding-Magnesium-Oxide-Dot-Cross-Diagram

Dot and cross diagram to show the ionic bonding in magnesium oxide

Calcium fluoride

  • Calcium is a Group 2 metal
    • It loses its 2 outer electrons to form a calcium ion with a +2 charge (Ca2+)
  • Fluorine is a Group 7 non-metal
    • It gains 1 electron to form a fluoride ion with a -1 charge (F-)
  • As before, the positive and negative ions are attracted to each other via an ionic bond
  • However, to cancel out the 2+ charge of the calcium ion, 2 fluorine atoms are needed
    • Each fluorine atom can only accept 1 electron from the calcium atom
    • 2 fluoride ions will be formed
  • Calcium fluoride is made when 1 calcium ion and 2 fluoride ions form ionic bonds, CaF2
  • The final ionic solid of CaF2 is neutral in charge

1.3-Chemical-Bonding-Calcium-Fluoride-Dot-and-Cross-Diagram

Dot and cross diagram to show the ionic bonding in calcium fluoride

Worked example: Dot & cross lithium nitride

1.3-Chemical-Bonding-Worked-example-Dot-cross-lithium-nitride

Answer

  • Lithium is a Group 1 metal
  • It loses its outer electron to form a lithium ion with a +1 charge (Li+)
  • Nitrogen is a Group 5 non-metal
  • It gains 3 electrons to form a nitride ion with a -3 charge (N3-)
  • To cancel out the -3 charge of the nitride ion, 3 lithium atoms are needed and 3 lithium ions will be formed
  • Lithium nitride is made when 1 nitride ion and 3 lithium ions form ionic bonds
  • The final ionic solid of Li3N is neutral in charge

1.3-Chemical-Bonding-Lithium-Nitride-Cross-Diagram

Dot and cross diagram to show the ionic bonding in lithium nitride

Worked example: Dot & cross aluminium oxide

1.3-Chemical-Bonding-Worked-example-Dot-cross-aluminium-oxide

Answer

  • Aluminium is a Group 3 metal
  • It loses its outer electrons to form an aluminium ion with a +3 charge (Al3+)
  • Oxygen is a Group 6 non-metal
  • It gains 2 electrons to form an oxide ion with a -2 charge (O2-)
  • To cancel out the negative and positive charges, 2 aluminium and 3 oxygen atoms are needed
  • Aluminium oxide is made when 2 aluminium ions and 3 oxygen ions form ionic bonds
  • The final ionic solid of Al2O3 is neutral in charge

1.3-Chemical-Bonding-Aluminium-Oxide-Cross-Diagram

Dot and cross diagram to show the ionic bonding in aluminium oxide

 

 

 

 

 

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