Radioactivity can be define as when certain atoms release energy in the form of tiny particles or waves. This happens because the atoms are unstable and trying to become more stable.

Radioactive elements are materials where the tiny parts inside them are always moving and changing. They give off energy in the form of small particles or waves to become more steady.

Radioactive elements include:

1. Uranium (U): Used in nuclear power plants and weapons.


2. Thorium (Th): Found in some rocks and used in certain types of reactors.


3. Radium (Ra): Formerly used in glow-in-the-dark paints and medical treatments.


4. Polonium (Po): Can be found in tobacco smoke and used in industry.


5. Radon (Rn): A gas that can accumulate in homes and buildings, posing health risks.