Answer: Mg is a cation and Cl is an anion
Explanation: In more detail, if you look at the periodic table, the group number (or columns) of the elements, describe how many valence electrons, or how many electrons the element has available to have a complete an electron shell. Magnesium being in group 2, it has one 2 electrons that will be "donated" to an anion that it bonds with. However, Chlorine being in group 17, (look at the single digit number for double digit groups), it has 7 valence electrons. Knowing that a full electron shell is usually 8 electrons, it needs only one. Since Magnesium has 2 valence electrons to give away, two atoms of Chlorine gas will then bind to the Magnesium, where the 2 Chlorine atoms will take the electrons to fill their shells. Magnesium Chloride, in terms of charges when in ions, [Mg]2+ and 2 [Cl]-1
