Uranium was discovered by Martin Heinrich Klaproth, a German chemist, in 1789.
Name: Uranium
Symbol: U
Atomic number: 92
Atomic weight: 238.03
State: solid
Group, period, block: n/a, 7, f
Color: silvery gray metallic
Classification: actinide
Electron configuration: 5f3 6d1 7s2
2,8,18,32,21,9,2
Physical properties
Density: 19.1 g/cm-3
Melting point: 1405.3 K,1132.2 °C,2070 °F
Boiling point: 4404 K,4131 °C,7468 °F
Atomic properties
Oxidation states: 6, 5, 4, 3[1], 2
Electronegativity: 1.38 (Pauling scale)
Ionization energies: 1st: 597.6 kJ·mol-1
Covalent radius: 196±7 pm
Van der Waals radius: 186 pm
- U
Electron Configuration
Isotopes
Uranium is a naturally occurring radioactive element that has no stable isotopes but has two primordial isotopes 238U and 235U. Naturally occurring uranium is composed of three major isotopes, 238U (99.2739 - 99.2752% natural abundance), 235U (0.7198 - 0.7202%), and 234U (0.0050 - 0.0059%). All three isotopes are radioactive. 238U has the longest half life, about 4.4683×109 years (close to the age of the Earth).