the.com/neptunium
the first synthetic element, a metal born past the edge of the periodic map.
means Neptunium is a silvery, radioactive metallic element with atomic number 93, the first transuranium element ever made, produced by bombarding uranium with neutrons.
from Named after the planet Neptune, following a neat cosmic logic: uranium had been named for Uranus, so the element just beyond it in the periodic table took the name of the planet just beyond Uranus. It was discovered in 1940, with 'Neptune' itself tracing back to the Roman god of the sea, whose name is of uncertain ancient origin.
- named after
- the planet beyond Uranus, as element 93
- discovered
- 1940 by Berkeley physicists from bombarded uranium
- in smoke detectors
- its isotope quietly decays in millions of homes
- densest neptunium
- twenty times heavier than water by volume
- half-life
- one isotope outlasts two million years
neptunium-237 — most stable isotope, half-life of 2.14 million years, used in neutron detectors
berkeley lab synthesis 1940 — first created by mcmillan and abelson at uc berkeley cyclotron, element 93