(12) Show the formation of the ionic compound Aluminum Oxide: i)use either
the LCM or Criss-Cross Method to establish the formula. ii)Show the transfer of
electrons and the formation of the cation(s)/Anion(s) in ionic bond formation.
[3]

Aluminium oxide is a ionic compound with formula of Al2O3.

Aluminium belongs to the group 3 and has the atomic number of 13. So it has an electronic configuration of [Ne] 3s2 3p1. So its valence shell has 3 electrons which can be donated to form the Al3+ cation.

On the other side, oxygen belongs to the group 16 with atomic number of 8. It has the electronic configuration of [He] 2s2 2p4. So it has 6 electrons in its outermost shell which can receive another 2 to form the stable octet.

So both aluminium and oxygen reacts to form the aluminium oxide whose formation is shown in the diagram. Both the images are taken from Google.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.