Final answer:
The balanced half-reaction for the oxidation of magnesium is Mg(s) → Mg²⁺(aq) + 2e⁻, illustrating that magnesium loses two electrons to become a Mg²⁺ cation.
Step-by-step explanation:
The question asks to write a balanced half-reaction for the oxidation of solid magnesium to aqueous magnesium cations. Oxidation involves the loss of electrons, and a half-reaction shows this process for one specific element.
The unbalanced half-reaction for the oxidation of magnesium is:
Mg(s) → Mg2+(aq)
Considering the conservation of charge and mass, the balanced half-reaction that includes the appropriate number of electrons lost in the process is:
Mg(s) → Mg2+(aq) + 2e-
This equation represents the oxidation of magnesium and shows that each magnesium atom loses two electrons to form a divalent cation, Mg2+.