Praseodymium (symbol Pr, atomic number 59) is a rare-earth metal used in powerful magnets and to colour glass yellow-green. It is classified as a lanthanide and sits in the lanthanide series (f-block), period 6 of the periodic table.
Overview
Praseodymium is the chemical element with atomic number 59 and the symbol Pr. With a standard atomic weight of 140.91, it is a lanthanide. In the periodic table it occupies the lanthanide series (f-block) and period 6, and under standard conditions it is normally a solid. Praseodymium is a rare-earth metal used in powerful magnets and to colour glass yellow-green.
Atomic structure
An atom of Praseodymium has 59 protons in its nucleus and, when neutral, 59 electrons arranged in the configuration [Xe] 4f3 6s2. Its standard atomic weight of 140.91 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Praseodymium was discovered in 1885 by Carl Auer von Welsbach. It follows Cerium (Ce) and precedes Neodymium (Nd) in order of atomic number.
| Atomic number | 59 |
|---|---|
| Symbol | Pr |
| Atomic mass | 140.91 |
| Category | Lanthanide |
| Group | — |
| Period | 6 |
| Electron configuration | [Xe] 4f3 6s2 |
| Phase at STP | Solid |
| Discovered | 1885 (Carl Auer von Welsbach) |