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What is Alpha,Beta & Gama Radiations.

Nuclear Chemistry

Nuclear reactions are very different from ordinary chemical reactions. Nuclear reactions, involve changes in the composition of the nuclei.  These extraordinary processes usually take place releasing tremendous amounts of energy.
            We know protons and neutrons are found in the nucleus of the atom; the electrons occupy the rest of the volume of the atom. The atomic number represents the number of protons in the nucleus and the mass number is the sum of protons and neutrons. Isotopes of an element vary in the number of neutrons in the nucleus and therefore have different atomic numbers. There are over 300 naturally occurring isotopes. Of these, 264 are stable, the remainder are unstable. These unstable isotopes undergo nuclear decay and are referred to as radioactive isotopes. If the atomic number (or number of protons) is changed, the element changes.

Types of radiation

Alpha Particles

Different forms of radiation may be emitted from an unstable radioactive nucleus. Energy is released and a new, more stable nucleus is formed. The 3 types of radiation to be considered in this section are: alpha, beta and gamma radiation. An alpha particle can be considered as a helium nucleus. Helium has 2 protons and 2 neutrons in its nucleus. If both of its electrons were removed, the result would be an alpha particle:

or a

Since there are two protons and no electrons, alpha particles are positively charged. Alpha particles are not very penetrating. Paper, clothing or a few centimeters of air can effectively shield against alpha particles. However, if ingested or inhaled, alpha particles can be hazardous.

Beta Particles

Beta particles are high-speed electrons emitted from the nuclei of decaying radioisotopes. Since these are electrons, they have a negative charge and a small mass, approximated as 0 amu.

or b

Beta particles may travel 2 or 3 meters through air. Heavy clothing, thick cardboard or one-inch thick wood will provide protection from beta radiation.

Gamma Radiation

Gamma radiation is very much like x rays. It has no charge, a very short wavelength and high energy. Gamma radiation is the most penetrating form of radiation considered in this section. It travels great distances through air (500 meters). To be protected from a gamma emitter, thick sheets of lead or concrete are required.

Besides alpha, beta and gamma radiation, other types of particles have been found to be emitted by radioactive isotopes. Examples of these other partilcles are: protons, neutrons and positrons. We have already studied protons and neutrons. A positron is a particle emitted from the nucleus that has the same mass as an electron but has a positive charge    ().


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