Chapter 9, Problem 9.79P

Interpretation Introduction

Interpretation:

Decay product of Americium-241 by alpha emission and amount of americium-241 left after radioactive decay for an elapsed time of 1000 yearsshould be determined.

Concept Introduction:

Radioactive decay is a process wherein a less stable radioactive nuclei form a more stable nuclei by loss of energy. This can be achieved by the loss of gain of elementary particles such as alpha, beta or positron particles. Alpha particles are nothing but a Helium nuclei (⁴₂ He). When a nucleus undergoes an alpha emission process, which is a type of elementary radioactive particle, the resulting product nuclei will have an atomic mass 4 unit lower and atomic number of 2 unit lower.

Radioactive decays follow first-order reaction kinetics.

For a first-order reaction the equation is:

$\text{l}n{\left[\text{a}\right]}_t=\text{l}n{\left[\text{a}\right]}_{\text{O}}–\lambda t$

where,

[A]_t = concentration of substrate at time ‘t’.

[A]_o = initial concentration of substrate at time ‘t=0’.

t = elapsed time.

$\lambda$ =decay constant.