U
Actinide
Uranium
Z 92A 238mass 238.03
Slow-motion stage
Uranium-238
proton
neutron
alpha particle (2p + 2n)
Parent nucleus · 238 nucleons
92 protons (coral) and 146 neutrons (blue) are packed together and held by the strong force.
A real decay takes about 10⁻²¹ s. At ⅓× this stage stretches it across eleven seconds.
Choose a reaction
Reaction
23892U23490Th+42He
Two protons and two neutrons leave together as one helium nucleus.
Z
9290
-2
A
238234
-4
n⁰
146144
-2
Energy released
4.27MeV
Alpha particle4.198 MeV
Mass convertedE = Δm c²0.00458 u
In joules6.84 × 10-13 J
Compared with a bonda C–C bond is 3.6 eV≈ 1,186,111 ×
Half-life of Uranium-238
4.47 billion years
The alpha leaves with 4.20 MeV; thorium-234 recoils with the rest.
The particle
- Charge
- +2
- Mass
- 4 u
- Speed
- About 5% of the speed of light
- Ionising power
- Very high
- Stopped by
- Stopped by a sheet of paper or dead skin