Group 3 of the Periodic Table
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Group 3 of the periodic table (also called Group IIIB) comprises the third column of transition metals and represents the first of the d-block elements, situated on the left edge of that block.
The elements of this group have an electron configuration ending with two electrons in the s orbital and one electron in the d orbital (for example, d¹s²). For this reason, they typically participate in bonding by losing three electrons, resulting in an oxidation state of +3.
Members of the Group
The two stable elements are scandium (Sc, atomic number 21) and yttrium (Y, atomic number 39). Both are silvery metals that react readily with oxygen in air, forming a protective oxide layer on the surface.
Chemical Properties
The chemistry of Group 3 is very similar to that of the rare earth elements. The +3 oxidation state is stable; the most common compounds are oxides (such as Sc₂O₃ and Y₂O₃) and halides. Atomic radius decreases down the group, and consequently chemical reactivity increases.
Applications and Occurrence
Scandium is commonly added to aluminum to produce lightweight, high-strength alloys and is used in metal-halide lamp phosphors. Yttrium is employed in color phosphors for displays, laser crystals, and superconductors such as YBCO. Both elements are typically recovered from ores that contain rare earth elements, using consistent chemical separation methods.