Ca
Alkaline earth metal
Calcium
Z 20A 40mass 40.078
Slow-motion stage
Calcium-40
proton
neutron
electron (β⁻)
Parent nucleus · 40 nucleons
20 protons (coral) and 20 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
4020Ca4021Sc+β⁻+ ν̄
A neutron turns into a proton. An electron and an antineutrino fly out.
Z
2021
+1
A
4040
no change
n⁰
2019
-1
Energy released
0.900MeVtypical value
Electron (max)0.900 MeV
Mass convertedE = Δm c²0.00097 u
In joules1.44 × 10-13 J
Compared with a bonda C–C bond is 3.6 eV≈ 250,000 ×
Measured beta energies fall between 0.02 and 3 MeV.
The particle
- Charge
- −1
- Mass
- 1/1836 u
- Speed
- Up to 99.9% of the speed of light
- Ionising power
- Moderate
- Stopped by
- A few millimetres of aluminium