Lutetium (metal)

   Lutetium, element number 71, is the last metal in the lanthanide series of rate-earth elements. It is like lanthanum and the other lanthanides in that its compounds are colorless and not magnetic. Lutetium was named after the Roman name of Paris, France.
   The lanthanide elements have properties remarkably alike. The similarity occurs because each element has two electrons in the outermost shell. Because of the great similarity in chemical properties, it is difficult to isolate one rare earth like lutetium from the others.
   Lutetium (symbol Lu) was first separated from ytterbium in 1907. It has an atomic weight of 174.97 (174.99, O=16). It is sometimes spelled lutecium.