Description: 3 parts:
- iodine-131 as an example to introduce the notion of half-life;
- carbon-14 as a second example;
- exercise on the topic of carbon dating.

Definitions

Radioactive decay: process by which an unstable atomic nucleus loses matter or energy by radiation.
A radioactive material containing unstable nuclei.
Three of the most common types of decay are alpha decay (α-decay), beta decay (β-decay), and gamma decay (γ-decay). 

Half-life: The time required for half the atoms of a particular radioisotope to decay into another isotope.