Sodium-22 Decay Calculation and Properties
Sodium-22 Decay Calculation
Sodium-22 undergoes positron emission according to the decay equation AiNa - ANe + 0.93. If this decay has a half-life of 2.60 years, we can calculate the mass of 72.5 g of sodium-22 that will remain after 15.6 years.
Decay Formula
A nucleus can split into two or more particles due to the instability of the nucleus.
Radioactive elements usually have unstable nuclei.
General decay formula:
Nt = N0 (1/2)^(T/t1/2)
Calculation
T = 15.6 years
t1/2 = 2.6 years
N0 = 72.5 g
Nt = 72.5 * (1/2)^(15.6/2.6)
Nt ≈ 1.13 g
Properties of Sodium-22
Sodium-22 (Na22) is produced by cosmic rays inducing the fragmentation of atmospheric argon. It is also generated during nuclear weapons testing with observed fallout levels higher than natural production. Na22 has a half-life of 2.6 years and undergoes β+ decay to stable Neon-22, emitting a positron in the process. A small fraction of the decay leads directly to the neon ground state.
What is the mass of sodium-22 remaining after 15.6 years if the initial mass is 72.5 g and the half-life is 2.6 years? The remaining mass of sodium-22 after 15.6 years is approximately 1.13 grams.