Final answer:
Mercury differs from other transition metals by being liquid at room temperature, less reactive, and more resistant to oxidation. It forms amalgams with other metals and can exhibit a unique 1+ oxidation state in addition to the common 2+ state for group 12 elements.
Step-by-step explanation:
Mercury is distinct amongst transition metals for several reasons. First and foremost, Mercury is the only metal that is liquid at room temperature (25 °C), differentiating it from zinc, cadmium, and other transition metals. While many metals can dissolve in mercury to form amalgams, which are mercury alloys, mercury itself exhibits unique chemical properties such as being less reactive and more difficult to oxidize than hydrogen. It does not displace hydrogen from acids, which most metals do, but it can react with strong oxidizing acids like nitric acid producing mercury nitrate, water, and nitrogen oxides.
Mercury is also unique in Group 12 of the periodic table, as it can sometimes exhibit an oxidation state of 1+ due to the presence of a diatomic Hg₂²+ ion. This is in addition to the typical 2+ oxidation state common in group 12 elements which include zinc, cadmium, and copernicium. Furthermore, mercury's properties contrast with other transition metals as they are generally characterized by high melting points and the ability to form stable cations and coordination compounds. Mercury's low reactivity and amalgam-forming ability make it an anomaly among its peers in the transition metal category.