Uranium (U)
“The heaviest primordial element on Earth, whose splitting atoms release a million-fold more energy than burning — the fuel of Rooppur, Bangladesh’s first nuclear power plant.”
How its electrons are arranged
Computed from the aufbau principle, with known real-world exceptions applied automatically.
The notes
Characteristics
- Electron configuration [Rn] 5f³ 6d¹ 7s² — period 7, f-block actinide; its chemistry swings between +4 (green solutions) and +6 (the yellow uranyl ion UO₂²⁺).
- Two headline isotopes: fissile U-235 (a mere 0.72% of natural uranium, half-life 704 million years) sustains chain reactions, while fertile U-238 (99.27%, half-life 4,470 million years — Earth’s own age) instead soaks up neutrons and can breed plutonium.
- One fissioning U-235 nucleus releases about 200 million electron-volts — roughly a million times the energy per atom of burning coal; a single fuel pellet packs the punch of about a tonne of coal.
- Patient radioactivity: U-238’s 4,470-million-year half-life means Earth’s birth-time uranium still endures — a few grams in every tonne of granite and about 3 micrograms dissolved in each litre of seawater.
A dense, silvery-grey metal — nearly twice as heavy as lead — that takes on a dark oxide coat and slowly crumbles in air. Freshly cut it gleams like steel, but the shine never lasts: uranium is a restless metal with a nuclear heart.
Where you meet it
✦ Uses
- Nuclear electricity: uranium dioxide pellets enriched to 3–5% U-235 power reactors worldwide — including the Rooppur Nuclear Power Plant at Ishwardi, Pabna, whose two Russian VVER-1200 units are Bangladesh’s first.
- Naval propulsion: submarines and aircraft carriers cruise for years between refuellings on compact highly enriched uranium cores.
- Medicine and research: reactors running on uranium fuel brew medical isotopes such as molybdenum-99 — the parent of technetium-99m used in hospital scans — and supply neutron beams for materials science.
- Depleted uranium, the almost-pure U-238 tailings of enrichment: its staggering density makes it ideal for aircraft counterweights, gamma-radiation shielding and armour-piercing ammunition.
- Reading Earth’s clock: the uranium–lead decay clock sealed inside zircon crystals fixed the age of Earth’s oldest known minerals at about 4,400 million years.
◍ Everyday examples
- Every Rooppur bulletin — turbine tests, fuel loading, 2,400 megawatts bound for the national grid — is Bangladesh’s own living uranium story on the news.
- The granite of Dinajpur’s Maddhapara hard-rock mine carries a few grams of uranium per tonne, as most granites do; so do the heavy minerals of Cox’s Bazar beach sands.
- Antique shops sometimes stock uranium (“vaseline”) glass, which flashes green under an ultraviolet torch — a harmless little souvenir of the nuclear age.
History & name
In 1789 the German apothecary-chemist Martin Heinrich Klaproth, dissolving a Bohemian pitchblende sample in his Berlin laboratory, precipitated a strange yellow substance and proclaimed a new element — naming it uranium after the planet Uranus, discovered only eight years earlier. His “metal” was in truth just an oxide; the real metal waited until 1841, when Eugène-Melchior Péligot reduced uranium tetrachloride with potassium in Paris. Then in 1896 came the twist that rewrote physics: Henri Becquerel found that a uranium salt fogged a wrapped photographic plate without any light at all — radioactivity itself, soon named and pursued by Marie Curie. Finally, in December 1938, Otto Hahn and Fritz Strassmann split uranium with neutrons, opening the door to reactors, bombs and the nuclear age.