Nuclear Chemistry

Following is a series of terms and concepts that are related to the topic of Nuclear Chemistry.

Alpha Emission:

Alpha particles are nuclear decay particles.

  •  They consist of two protons and two neutrons.
  • In essence, they are equivalent to a helium nucleus.
  • The particles are expelled from a nucleus at a fairly low speed, approximately one-tenth the speed of light.
  • They are a minimal health risk to people unless ingested or inhaled.
  • The large mass nuclei tend to use alpha emission because it is a quick way for a large mass atom to lose a lot of nucleons.

Beta Emission:

 Beta Emission is a nuclear decay process. It is the process that ejects a high speed electron from an unstable nucleus. The electron is formed on the spot within the nucleus by the breakdown of a neutron into a proton and electron. The electron is released from the system. The proton that was formed remains behind in the nucleus. As a result of the addition of the proton, the atomic number of an element increases during beta emission. Beta emission can be a significant health risk.

Binding Energy:

 Binding Energy is the energy that a nucleus releases in the process of trying to stabilize itself. The nucleus converts some of its own mass into energy. That energy is ejected from the nucleus. The process of the loss of energy will then move the system further down an energy level diagram. Thus, the system becomes more stable. This process is necessary to relieve the instability associated with having a large mass of positively charged protons so close together.

Binding Energy Curve:

 The Binding Energy Curve helps to understand the ideas behind fission and fusion. It is a graph that plots the Binding Energy per Nucleon as a vertical coordinate and the Mass Number of the elements as the horizontal coordinate.

 The graph peaks at a mass number of 56. The more binding energy that is released per nucleon, the more stable a nucleus is. Since 56 is the high point of the graph, it means that any nucleus with a mass number of 56 will achieve the maximum stability possible. In theory, all nuclei will try to become larger or smaller, as necessary, so that they will eventually have a total of 56 nucleons in their structures.

Elements to the right of 56 would like to become smaller. They do so with the process known as fission. Elements to the left of 56 would like to become larger. They do so with the process known as fusion.


 Fission is the process known as "splitting the atom." During fission, a large mass nucleus is split into two or more smaller mass nuclei. Hopefully during fission, the resulting new nuclei will have mass numbers that are closer to 56. During the process large quantities of energy are released as the products move up the Binding Energy Curve. Fission is the currently used process for the production of nuclear energy.


 Fusion is the process that unites small mass nuclei into a larger mass nucleus. During the fusion process, the newly formed nucleus will have a mass number that is closer to 56. During fusion extremely large quantities of energy are released as the nuclei move up the Binding Energy Curve. This is a much more efficient process than fission. It produces considerably more energy that fission. Unfortunately, it is very difficult to accomplish and is not being utilized as a source of energy by society.

Gamma Emission:

 Gamma Emission occurs primarily after the emission of a decay particle. Gamma is a form of high energy electromagnetic radiation. After a particle is ejected from a nucleus the system may have some slight excess of energy, or exist in a metastable state. This slight excess of energy is released as gamma. Gamma emission will not change the isotope or the element. The wavelength of the emitted gamma radiation will be be unique to each isotope. Gamma emission is a significant health risk.

Mass Defect:

 Mass Defect is the mass in a nucleus that is converted into energy. This energy is then ejected from the nucleus to stabilize the system. The mass defect will be the difference between the theoretical mass, calculated as the sum of the parts of the nucleus, and the experimental mass. This difference will be the mass that was lost in the production of energy.

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Updated June 30, 2008