Which corresponds to the composition of the ion typically formed by magnesium?

The ion composition of Magnesium is 12,10, 2+.

Magnesium is a chemical element with symbol Mg and an atomic number 12, it has 12 protons, and 12 electrons with a chemical configuration of 2:8:2. It requires to loose two electrons to form a stable configuration forming a cation (positively charged ion) with a charge of + 2 and a configuration of 2:8 (12 protons and 10 electrons).