Praseodymium, atomic no. 59, symbol Pr, weight at 140.91, resembles the typical trivalent rare earth...

Cerium, atomic no. 57, symbol Ce, weight at 140.12, is the most abundant of the rare earths. It is s...

Lanthanum, atomic no. 57, symbol La, weight at 138.91, is the first element in the rare earth or lan...

Yttrium, atomic no. 39, symbol Y, weight at 88.91, has the highest thermo-dynamic affinity for oxyge...

...