* Carbonate ion: The carbonate ion is a polyatomic ion with the formula CO₃²⁻. It has a charge of -2.
* Magnesium: Magnesium (Mg) is a metal and forms a cation with a charge of +2 (Mg²⁺).
Combining them: When magnesium and carbonate ions combine, they form the ionic compound magnesium carbonate (MgCO₃). The charges balance out as follows:
* Mg²⁺ + CO₃²⁻ → MgCO₃
Therefore, there's no such thing as a "carbonate ion Mg 2". The question likely intended to ask about the formula and charge of the carbonate ion and how it combines with magnesium.
