Examples of Ionic Bonding
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
Dot and cross diagram to show the ionic bonding in sodium chloride
Sodium gives its one outer electron to chlorine forming the ionic compound, 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
Dot and cross diagram to show the ionic bonding in magnesium oxide
Magnesium gives both outer electrons to oxygen forming the ionic compound, 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
Dot and cross diagram to show the ionic bonding in calcium fluoride
Calcium gives away both outer electrons. Each fluorine receives one of those electrons forming the ionic compound, calcium fluoride
Worked example
Dot & cross lithium nitride
Draw a dot and cross diagram for lithium nitride, Li3N.
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:
Worked example
Dot & cross aluminium oxide
Draw a dot and cross diagram for aluminium oxide, Al2O3.
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:
