What is the chemical symbol for Cadmium?

The chemical symbol for Cadmium is simply "Cd." This symbol represents the element itself on the periodic table and is used universally in chemical equations and discussions.

The other options present variations that don't accurately describe the element in its basic form. For instance, "Cd(2+)" indicates a specific ion of Cadmium, specifically the divalent cation, which appears when Cadmium loses two electrons during chemical reactions. While this representation is important in understanding the behavior of the element as a cation in compounds, it does not represent the element itself.

Similarly, "Cd(-)" suggests an anionic form of Cadmium, which is not commonly encountered in chemistry, as Cadmium typically exists in a cationic state in compounds. "CdO" refers to Cadmium oxide, a compound formed when Cadmium reacts with oxygen, but it does not represent the elemental form of Cadmium.

Thus, "Cd" is the correct choice as it is the universally recognized symbol for the element Cadmium.