Radioactivity Review

Across
3.	This type of radiation particle is capable of penetrating only the very outer layer of living skin cells.
5.	The charge on an alpha particle
8.	The breakdown of an unstable, radioactive element from a parent element into a daughter element.
11.	Common shield for gamma waves.
12.	This occurs when an unstable nucleus breaks down into two smaller nuclei and releases energy.
15.	The charge on a beta particle.
16.	using the known half-life and proportions of a sample to determine the age of something.
18.	a beta particle
20.	This type of radiation can pass through the body sometimes causing health effects.
21.	One of two or more forms of the same element.

Down
1.	This is a heavy element which can fission. It undergoes beta decay to become Americium.
2.	This common material can shield alpha particles.
4.	A particle that is the antimatter opposite of an electron.
6.	This type of radiation causes the most damage once it gets inside the body.
7.	The time period during which a radioactive isotope decays to half its value is called this.
9.	this doesn't change with beta particle emission.
10.	This chronic health effect can occur due to radiation exposure.
13.	This element is a common alpha particle emitter.
14.	This type of naturally-occurring radioactive gas is the most common cause of lung cancer in non-smokers.
17.	This is a highly radioactive man-made gas. It is an isotope of hydrogen and sometimes found in heavy water.
19.	The breakdown of an unstable, radioactive element from a parent element into a daughter element.