Here's why:

* Metals tend to form cations: Scandium is a metal. Metals typically lose electrons to achieve a stable electron configuration, forming positively charged ions called cations.

* Scandium's electron configuration: Scandium has an electron configuration of [Ar] 3d¹ 4s². It tends to lose its three outermost electrons (one from the 3d orbital and two from the 4s orbital) to form a +3 ion (Sc³⁺).

Let me know if you'd like more details on how to determine if an element will form a cation or anion!