Chemistry: 1908

Rutherford, Ernest (1871-1937), a British physicist, established the nuclear model of the atom in 1911. Later, he became the first person to break up the nucleus of an atom. Because of his many contributions to science, he is often regarded as the father of nuclear science.

In the nuclear model of the atom, Rutherford theorized that atoms are constructed much like the solar system. That is, a heavy part, called the nucleus, forms the center of each atom. Particles of negative electricity, called electrons, form the outer part, most of which consists of empty space. In 1913, Niels Bohr combined this nuclear model of the atom with the quantum theory in the Bohr theory of atomic structure.

In 1902, Rutherford and the British chemist Frederick Soddy published their discovery of atomic transmutation. Their observations proved that radioactive elements give off electrically charged particles known as alpha and beta particles. This process changes the parent (original) atom into a daughter atom. The daughter atom is a different chemical element. This achievement won Rutherford the 1908 Nobel Prize in chemistry.

Rutherford produced the first artificial atomic transmutations in a series of experiments from 1917 to 1919. He bombarded nitrogen atoms with alpha particles. In rare collisions, an alpha particle pushed a proton, a positively charged particle, out of a nitrogen nucleus. At the same time, the nucleus absorbed the alpha particle, becoming an oxygen nucleus.

Rutherford was born in Nelson, New Zealand. He taught at McGill University in Montreal, the University of Manchester, and Cambridge University. In 1903, he was elected a Fellow of the Royal Society. He wrote several books, including Radioactive Substances and Their Radiations (1913). In 1931, he received the title of Baron Rutherford of Nelson.

Contributor: Roger H. Stuewer, Ph.D., Professor of the History of Science and Technology, University of Minnesota.

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