93Np[237]
Neptunium
ActinidesHeavy, radioactive metals. Most of them are made only in laboratories.
[Rn] 5f⁴ 6d¹ 7s²
- Atomic number
- 93
- Atomic mass
- [237]
- Protons
- 93
- Neutrons
- 144
- Electrons
- 93
- Shells
- 2, 8, 18, 32, 22, 9, 2
- State at 25 °C
- Solid
- Position
- Period 7, f-block
Proton (+)Neutron (0)Electron (−)
Discovered byEdwin McMillan and Philip Abelson, 1940Edwin McMillan: 2 elements
The first element heavier than uranium ever made. Named after Neptune, the planet after Uranus.
Did you know?
- It was the first transuranium element.
- It's a by-product of nuclear reactors.
Where it's found
- Made in nuclear reactors
- Tiny traces in uranium ore
What it's used for
- Neutron detectors
- Research
Try it
There's no safe home experiment for Neptunium. Explore it with the animated atom above instead.