 |
| Name |
protactinium |
| Symbol |
Pa |
| Atomic Weight |
231.03588 |
| Atomic Number |
91 |
| CAS ID |
7440-13-3 |
| Group Number |
|
| Group Name |
Actinoid |
| Period Number |
7 |
| Origin of Name |
Greek, protos = "first." |
| Year Discovered |
1917 |
| Discovery Credits |
Discovered by Otto Hahn and Lise Meitner at
Berlin, by K. Fajans at Karlsruhe, Germany, and by F. Soddy, J. A.
Cranston, and A. Fleck at Glasgow, Scotland. |
| Class |
Metallic |
| Color |
Silvery Metallic |
| Standard State |
Solid at 77 F & 298 K |
| Description |
Radioactive, silvery metal found naturally in
uranium ores. Attacked by oxygen, steam, and acids, but not by alkalis.
Little used. Primarily occurs as a trace amount (a few ppm) in uranium minerals where it is a decay
product of uranium |
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