Uranium (symbol U, atomic number 92) is the heaviest naturally abundant element, the primary fuel of nuclear reactors and weapons. It is classified as a actinide and sits in the actinide series (f-block), period 7 of the periodic table.
Overview
Uranium is the chemical element with atomic number 92 and the symbol U. With a standard atomic weight of [238], 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. Uranium is the heaviest naturally abundant element, the primary fuel of nuclear reactors and weapons.
Atomic structure
An atom of Uranium has 92 protons in its nucleus and, when neutral, 92 electrons arranged in the configuration [Rn] 5f3 6d1 7s2. Uranium has no stable isotope; the value [238] refers to the mass number of its most stable or most commonly produced isotope.
Discovery and place in the table
Uranium was discovered in 1789 by Martin Heinrich Klaproth. It follows Protactinium (Pa) and precedes Neptunium (Np) in order of atomic number.
| Atomic number | 92 |
|---|---|
| Symbol | U |
| Atomic mass | [238] |
| Category | Actinide |
| Group | — |
| Period | 7 |
| Electron configuration | [Rn] 5f3 6d1 7s2 |
| Phase at STP | Solid |
| Discovered | 1789 (Martin Heinrich Klaproth) |