The accompanying graph illustrates the decay of ⁸⁸₄₂Mo, which decays via positron emission. (a) What is the halflife of the decay? [Section 21.4]

Key Concepts

Radioactive Decay

Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting radiation. This can occur in various forms, including alpha particles, beta particles, or gamma rays. In the case of positron emission, a proton in the nucleus is transformed into a neutron, releasing a positron and a neutrino. Understanding this process is crucial for analyzing the decay of isotopes like 88Mo.

Half-Life

The half-life of a radioactive substance is the time required for half of the radioactive nuclei in a sample to decay. This concept is fundamental in nuclear chemistry and helps in predicting the behavior of radioactive materials over time. The half-life is a constant for each isotope and can be determined from decay graphs, where the time taken for the mass to reduce to half its initial value is measured.

Decay Curve

A decay curve is a graphical representation of the decrease in the quantity of a radioactive substance over time. It typically shows an exponential decline, where the y-axis represents the remaining mass or activity, and the x-axis represents time. Analyzing the shape of the decay curve allows one to determine the half-life and understand the kinetics of the decay process, which is essential for solving problems related to radioactive isotopes.