Certain highly reactive metals are never found in nature as free elements due to their strong affinity for other elements, particularly oxygen. These include alkali metals like sodium and potassium, alkaline earth metals like calcium and magnesium, and reactive transition metals like aluminum. These metals readily react with atmospheric oxygen, moisture, or other elements to form oxides or compounds. As a result, they exist in nature primarily in the form of minerals, ores, or compounds rather than as uncombined, free elements. Extracting these metals often involves various chemical and metallurgical processes to isolate them from their natural compounds.