High Quality Content by WIKIPEDIA articles! Radiochemistry is the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to a substance being described as being inactive as the isotopes are stable). Much of radiochemistry deals with the use of radioactivity to study ordinary chemical reactions. Radiochemistry includes the study of both natural and man-made radioisotopes. All radioisotopes are unstable isotopes of elements undergo nuclear decay and emit some form of radiation. The radiation emitted can be one of three types, called alpha, beta, or gamma radiation. These three types of radiation can be distinguished by their difference in penetrating power. Alpha can be stopped quite easily by a few centimetres in air or a piece of paper and is equivalent to a helium nucleus. Beta can be cut off by an aluminium sheetjust a few millimetres thick and are electrons. Gamma is the most penetrating of the three and is a massless chargeless high energy photon.