What ion is scandium most likely to form? Is this a cation or an anion?

Scandium is most likely to form a cation, specifically the Sc³⁺ ion. As a transition metal, scandium has a tendency to lose electrons to achieve a stable electron configuration, which is characteristic of cations.

In its elemental form, scandium has the electron configuration of [Ar] 3d¹ 4s². When it loses three electrons, it first loses the two electrons in the 4s orbital and then the one electron from the 3d orbital, resulting in the Sc³⁺ ion. This ion is positively charged due to the loss of electrons, which makes it a cation rather than an anion.