Like everything we see in the world, isotopes are a type of atom, the smallest unit of matter that retains all the chemical properties of an element. Isotopes are forms of a chemical element with ...

If you would like to learn more about the IAEA’s work, sign up for our weekly updates containing our most important news, multimedia and more. About three percent of the Earth's water is freshwater.

This isotope is found at a ratio of about one per 2,500 helium-4 ions, the latter being the common version of helium. The sun just released a burst of a rare form of helium known as helium-3 (3 He).