Th
Actinide
Thorium
Z 90A 232mass 232.04
Slow-motion stage
Thorium-232
proton
neutron
alpha particle (2p + 2n)
Parent nucleus · 232 nucleons
90 protons (coral) and 142 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
23290Th22888Ra+42He
Two protons and two neutrons leave together as one helium nucleus.
Z
9088
-2
A
232228
-4
n⁰
142140
-2
Energy released
4.08MeV
Alpha particle4.013 MeV
Mass convertedE = Δm c²0.00438 u
In joules6.54 × 10-13 J
Compared with a bonda C–C bond is 3.6 eV≈ 1,134,167 ×
Half-life of Thorium-232
14.05 billion years
The start of a decay chain that ends at lead-208.
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