How is the oclet rule applied to the atomic representation of MgCl2?

Question

How is the oclet rule applied to the atomic representation of MgCl2?

Answer 1

Chlorine has 7 valence electrons, magnesium has 2.  So the magnesium atom donates one electron to each of the chlorine atoms, creating an octet for both chlorine atoms, like

. .

:Cl:

. .

Mg

. .

:Cl:

. .

Answer 2

The bonds between Mg and Cl are predominately ionic.  Therefore the Cl atoms will have octets by virtue of the electrons shared with Mg.  Because of the greater ionic character in these bonds, the Mg does not exhibit an octet, unless you consider the remaining eight 2s and 2p electrons.