Oxidising and Reducing Agents

Any species that accepts electrons from another species is an oxidising agent because the other species has been oxidised.Any species that donates electrons to another species is a reducing agent because the other species has been reduced.Fluorine is the most powerful oxidising agent because of its small size and its tendency to accept electrons from other atoms.Metals tend to lose electrons and transfer them to non-metals. When a metal reacts with a non-metal, metals are the reducing agents and non-metals are the oxidising agents.
In the reactionMg(s) + Cl₂(g) → MgCl₂(s)Magnesium loses 2 electrons and becomes Mg²⁺ so chlorine oxidises magnesium.Each of the two chlorine atoms gains an electron and becomes 2Cl^- so magnesium reduces chlorine.