Ra
Alkaline earth metal
Radium
Z 88A 226mass 226
Slow-motion stage
Radium-226
proton
neutron
alpha particle (2p + 2n)
Parent nucleus · 226 nucleons
88 protons (coral) and 138 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
22688Ra22286Rn+42He
Two protons and two neutrons leave together as one helium nucleus.
Z
8886
-2
A
226222
-4
n⁰
138136
-2
Energy released
4.87MeV
Alpha particle4.785 MeV
Mass convertedE = Δm c²0.00523 u
In joules7.80 × 10-13 J
Compared with a bonda C–C bond is 3.6 eV≈ 1,353,056 ×
Half-life of Radium-226
1,600 years
Its alpha decay is what fills a room with radon gas.
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