# What is meant by the half-life of a radioactive isotope?

##### 1 Answer

Nov 7, 2015

Isotopes are atoms of the same element with a different number of neutrons.

#### Explanation:

A radioactive isotope decays overtime. This is due to its unstable nuclei. Hence, overtime, they break down and form a completely different type of atom.

Essentially, the time taken for the number of nuclei in the isotope to half. This number varies among isotopes too.

For example, the half-life of carbon-14 is 5,715 years, but the half-life of francium-223 is just 20 minutes.