yttrium is a chemical elemental metal with an atomic number of 39, a chemical symbol of y, and an atomic weight of 88.905(abridged). it is classified as a transition metal. it is atomic number 39 on the periodic table. it is silvery-white, solid ant room temperature, and tends to form crystals. in chunk form, it is unreactive in air, but powdered yttrium may burn at 400 degrees celsius. it has several uses, which include lasers, tv's, and metallurgy.