Californium (symbol Cf, atomic number 98) is a synthetic actinide used as a portable neutron source. It is classified as a actinide and sits in the actinide series (f-block), period 7 of the periodic table.
Overview
Californium is the chemical element with atomic number 98 and the symbol Cf. With a standard atomic weight of [251], it is a actinide. In the periodic table it occupies the actinide series (f-block) and period 7, and under standard conditions it is normally a solid. Californium is a synthetic actinide used as a portable neutron source.
Atomic structure
An atom of Californium has 98 protons in its nucleus and, when neutral, 98 electrons arranged in the configuration [Rn] 5f10 7s2. Californium has no stable isotope; the value [251] refers to the mass number of its most stable or most commonly produced isotope.
Discovery and place in the table
Californium was discovered in 1950 by Glenn T. Seaborg et al.. It follows Berkelium (Bk) and precedes Einsteinium (Es) in order of atomic number.
| Atomic number | 98 |
|---|---|
| Symbol | Cf |
| Atomic mass | [251] |
| Category | Actinide |
| Group | — |
| Period | 7 |
| Electron configuration | [Rn] 5f10 7s2 |
| Phase at STP | Solid |
| Discovered | 1950 (Glenn T. Seaborg et al.) |