Final answer:
Most metals are reactive and combine with other elements, unlike silver which can be found as nuggets or in veins. Easily accessible surface deposits of native metals have mostly been depleted. Metals with higher reactivity, like aluminum, must be extracted from minerals through various processes.
Step-by-step explanation:
Most metals do not occur naturally in their pure form, unlike silver, which can be found as nuggets or in veins. The rarity of native metals like silver is due to the reactivity of most metals; they tend to combine with other elements to form minerals. Copper and gold are notable exceptions, like silver, they can also be found in their metallic state due to their low reactivity. The reason we find fewer native metals today is that easily accessible surface metal deposits have been exhausted over time. Metals such as iron used in making steel, often require extraction processes from their ores; for example, the smelting of iron ores to produce steel iron, and steel (stainless). Additionally, metals like aluminum do not occur freely due to their high reactivity and instead must be extracted from minerals like bauxite through processes like electrolysis.