Isotopes are alternative “versions” of elements that have a different atomic mass but the same atomic number. The atomic number of an element is determined by the number of protons present on its atom, while the atomic mass is calculated based on the present neutrons. Isotopes of the same element have different amounts of neutrons, as compared to protons. There two main types of isotopes: radioactive and stable. Both types are used widely in several industries and fields of study.
Stable isotopes have a stable proton-neutron combination and do not display any sign of decay. This stability comes from the amount of neutrons present in an atom. If an atom has too many or too little neutrons, it tends to disintegrate and become unstable. Since stable isotopes do not decay, it does not pose any physiologically dangerous effects to humans and other living things.
Uses of Stable Isotopes
Stable isotopes of oxygen, hydrogen, sulfur, nitrogen and carbon are used in environmental and ecological experiments. One scientific procedure using a stable isotope is geochemistry; it is a field of geology that studies the chemical composition of geologic materials, such as minerals and rocks. By using stable isotopes, geochemists can determine the age of the geologic material they are studying.
Radioactive isotopes have an unstable proton-neutron combination. These isotopes decay, often emitting certain types of radiation that include alpha, beta and gamma rays. There are also several types of radioactive isotopes depending on the creation process: long-lived, cosmogenic, anthropogenic and radiogenic.
Long-lived radioactive isotopes emerged during the creation of the solar system, while cosmogenic radioactive isotopes occur as a reaction of the atmosphere to cosmic rays emitted by stars. Anthropogenic isotopes are purely man-made and created through nuclear activities, such as weapons testing and nuclear fuel, while radiogenic isotopes are the end result of radioactive decay.
Uses of Radioactive Isotopes
Radioactive isotopes are used in agriculture, food industry, pest control, archeology and medicine. Radiocarbon dating, which measures the age of a carbon-bearing item, uses a radioactive isotope of carbon known as carbon-14. In medicine, gamma rays emitted by radioactive elements are used to detect tumors inside the human body. Food irradiation -- the process of exposing food to a controlled level of gamma rays -- kills many types of bacteria, making food safer to eat.