Iron is more reactive compared to gold, silver, and copper due to its position on the periodic table and its metallic properties. As you move across a period from left to right, the reactivity of metals generally decreases. Iron, found in Group 8 of the periodic table, is positioned towards the left side and has a larger atomic radius and fewer valence electrons compared to the other metals listed. This allows iron to lose electrons more readily, making it more reactive.
In contrast, gold and silver are located further to the right within the periodic table. These metals are considered noble metals, primarily because they have lower tendencies to lose their valence electrons and engage in chemical reactions. Copper, while somewhat more reactive than gold and silver, is still less reactive than iron. Therefore, iron’s reactivity aligns with periodic trends, marking it as the most reactive choice among the options provided.