ChemGlobe: Scandium: Electronic, thermal, and steric data along with an isotope table.
ChemicalElements.com: Scandium: Basic information, atomic structure, and isotopes.
Discovery of Scandium: Article by Lars Fredrick Nilson.
EnvironmentalChemistry.com: Scandium: Atomic structure, chemical and physical properties, and table of nuclides.
It's Elemental: Scandium: Basic physical and historical information.
LANL: Scandium: History, sources, properties, costs, and uses.
Scandium: Data tables and historic information.
USGS Minerals Information: Scandium: Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Visual Elements: Scandium: Image, animation, sources, use, physical information, and ionisation energies.
WebElements: Scandium: Extensive information on history, uses, occurrence, compounds, and properties of the element.
Wikipedia: Scandium: Properties of the element, including its history, applications, and characteristics.