Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the first and the prototype of the l

Ytterbium is a chemical element; it has symbol Yb and atomic number 70. It is a metal, the fourteenth element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation