Radioactive decay why does it happen

Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email. Anne Marie Helmenstine, Ph. Chemistry Expert. Helmenstine holds a Ph. She has taught science courses at the high school, college, and graduate levels. Facebook Facebook Twitter Twitter. Updated December 04, Featured Video. Cite this Article Format. Helmenstine, Anne Marie, Ph. Why Does Radioactive Decay Occur? What Is Radioactivity? What is Radiation?

Nuclear Isomer Definition and Examples. However, all elements have an unstable form. Unstable forms emit ionizing radiation and are radioactive. There are some elements with no stable form that are always radioactive, such as uranium. Elements that emit ionizing radiation are called radionuclides. When it decays, a radionuclide transforms into a different atom - a decay product. The atoms keep transforming to new decay products until they reach a stable state and are no longer radioactive.

The majority of radionuclides only decay once before becoming stable. Those that decay in more than one step are called series radionuclides. The series of decay products created to reach this balance is called the decay chain decay chain The series of decays or transformations that radionuclides go through before reaching a stable form. For example, the decay chain that begins with Uranium culminates in Lead, after forming intermediates such as Uranium, Thorium, Radium, and Radon Radioactive decay involves the spontaneous transformation of one element into another.

The only way that this can happen is by changing the number of protons in the nucleus an element is defined by its number of protons. There are a number of ways that this can happen and when it does, the atom is forever changed. There is no going back -- the process is irreversible. This is very much like popping popcorn.

When we pour our popcorn kernels into a popcorn popper, the is no way to know which will pop first. And once that first kernel pops, it will never be a kernel again And coincidentally, much yummier!

The atoms that are involved in radioactive decay are called isotopes. In reality, every atom is an isotope of one element or another. However, we generally refer to isotopes of a particular element e.

The number associated with an isotope is its atomic mass i. The element itself is defined by the atomic number i. Only certain isotopes are radioactive and not all radioactive isotopes are appropriate for geological applications -- we have to choose wisely. Those that decay are called radioactive or parent isotopes; those that are generated by decay are called radiogenic or daughter isotopes. The unit that we use to measure time is called half-life and it has to do with the time it takes for half of the radioactive isotopes to decay see below.

Half-life is a very important and relatively difficult concept for students. Mathematically, the half-life can be represented by an exponential function, a concept with which entry-level students may not have much experience and therefore may have little intuition about it. A nucleus consists of protons and neutrons held together by powerful forces. Certain combinations are more stable than others. Within one element—and to be careful, let's assume we are talking about one nuclide or one isotope of one element —every atom has exactly the same combination of protons and neutrons.

Every once in a long while, however, the jiggles might line up or form a resonance that sends the nucleus across the limit of its cohesion, and the nucleus splits. A nuclide with a shorter half-life less stable will violate its binding energy sooner, statistically, than will a nuclide with a longer half-life more stable.