Radioactivity

1. - The time it takes for half of the atoms in a sample of a radioactive substance to decay.
4. - A subatomic particle with no charge that is found in the nucleus of an atom.
8. - A device that measures ionizing radiation.
9. - Energy emitted in the form of waves or particles.
11. - A type of ionizing radiation consisting of helium nuclei.
13. - Exhibiting or caused by radioactivity.
14. - The presence or introduction of radioactive substances into an environment.

2. - Atoms of the same element that have different numbers of neutrons.
3. - The process by which two light nuclei combine to form a heavier nucleus, releasing energy.
5. sickness - A group of symptoms that occur after exposure to high levels of ionizing radiation.
6. - A type of ionizing radiation consisting of high-energy photons.
7. - A type of ionizing radiation consisting of electrons or positrons.
9. - An isotope of an element that is radioactive.
10. - The process by which a radioactive nucleus emits radiation and transforms into a different nucleus.
12. - The process by which a heavy nucleus splits into two or more lighter nuclei, releasing energy.