Magnesium metal is placed in a solution containing Sn²⁺ ions, and tin deposits on the strip. Which half-reaction represents the oxidation occurring?

Core Concept

Magnesium outranks tin in the activity series, so each magnesium atom surrenders two electrons and enters solution as Mg²⁺. Those freed electrons travel to Sn²⁺, plating tin metal onto the strip. Oxidation half-reactions always display electrons as products on the right-hand side of the arrow, which is the fastest structural cue.