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3.3: Three Types of Radioactivity

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  • Learning Objective

    Differentiate between alpha particles, beta particles and gamma rays.

    Ernest Rutherford, (30 August 1871 – 19 October 1937), was a New Zealand who came to be known as the father of . While working in Thomson’s laboratory shortly after Thomson discovered the electron, Rutherford showed that compounds of uranium and other elements emitted at least two distinct types of radiation. One was readily absorbed by matter and seemed to consist of particles that had a positive charge and were massive compared to electrons. Because it was the first kind of radiation to be discovered, Rutherford called these substances alpha (α) particles. Rutherford also showed that the particles in the second type of radiation, beta (β) particles, had the same charge and mass-to-charge ratio as Thomson’s electrons; they are now known to be high-speed electrons. In 1908 was awarded the "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances", for which he was the first Canadian and Oceanian Nobel laureate. A third type of radiation, gamma (γ) rays, was discovered somewhat later and found to be similar to the lower-energy form of radiation called x-rays, now used to produce images of bones and teeth.

    Table \(\PageIndex{1}\): Names, Symbols, Representations, and Descriptions of the most common types of radioactivity.



    An alpha particle is a high energy helium nucleus.

    A beta particle is a high energy electron.

    A gamma ray is a very high energy electromagnetic radiation

    Contributors and Attributions

    • CK-12 Foundation by Sharon Bewick, Richard Parsons, Therese Forsythe, Shonna Robinson, and Jean Dupon.

    • TextMap: Chemistry-The Central Science (Brown et al.)
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