Mg

Magnesium-21

Protons (Z)

12

Neutrons (N)

9

Mass number

21

Half-Life

120.0 ms

Abundance

---

Mass

21.012 u

Mass Excess

10,903.9 keV

Spin

5/2+

Discovered

1963

Binding energy per nucleon

7,105 keV

Neutron separation energy

14,645 keV

Proton separation energy

3,236 keV

Decay Mode

β⁺pα0.016%

Decay chain

Magnesium-21Z 12 · N 9120.0 ms
β⁺79.768%
β⁺100%