Radioactive Decay of Transuranic Elements

By Prayush Singh

Introduction to Radioactive Decay

• Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting ionizing particles or radiation. The emission is spontaneous in that the nucleus decays without collision with another particle. This decay, or loss of energy, results in an atom of one type, called the parent nuclide, transforming to an atom of a different type, named the daughter nuclide.

•2 main types of radiation in decay of transuranic elements – Alpha, and Beta radiation.

•Alpha particles consist of two protons and two neutrons. When an atom emits an alpha particle, the atom's mass number decreases by four due to the loss of the four nucleons in the alpha particle. The atomic number of the atom goes down by exactly two, as a result of the loss of two protons – the atom becomes a new element.

•Beta particles are high-energy, high-speed electrons or positrons emitted during radioactive decay. There are two forms of beta decay, β− and β+, which respectively emit the electron and the positron.

Plutonium-239(half-life: 24,110)

alpha decay

Radioactive Decay of Plutonium-239

Over the course of 80.8 Million YearsUranium-235 (half-life: 704,000,000)

alpha decay

Thorium-231(half-life: 25.2 hours)

beta decay

Lead-207(stable)

Thallium-207(half-life: 4.77 minutes)

beta decay

Bismuth-211(half-life: 2.15 minutes)

alpha decay

Protactinium-231(half-life: 32,700 years)

alpha decay

Actinium(half-life:21.8 years)

beta decay

Thorium-227(half-life: 18.72 days)

alpha decay

Radium-233(half-life:11.43 days)

alpha decay

Lead-211(half-life: 36.1 minutes)

beta decay

Radon-219(half-life: 3.96 seconds)alpha decay

Polonium-215(half-life: 1.78 milliseconds)

alpha decay