What elements are reducing agents?

Reducing agents are substances that donate electrons to another species in a chemical reaction, thereby reducing that species' oxidation state. Common elements that act as reducing agents include alkali metals (like sodium and potassium), alkaline earth metals (like magnesium and calcium), and nonmetals such as hydrogen. Transition metals, particularly those in lower oxidation states, can also serve as effective reducing agents. These elements facilitate reduction processes in various chemical reactions, including redox reactions.