365: Chemistry for Life
DAY 42

Frederick Soddy

British radiochemist Frederick Soddy coins the word "isotope" for elements that appeared to occupy the same place on the periodic table.

Credit: Nobel Foundation

Frederick Soddy, the son of Benjamin Soddy, a London merchant, was born at Eastbourne, Sussex, England, on September 2, 1877. He was educated at Eastbourne College and the University College of Wales, Aberystwyth.

In 1895 he obtained a scholarship at Merton College, Oxford, from which University he graduated in 1898 with first class honours in chemistry. After two years of research at Oxford he went to Canada and from 1900 to 1902 was Demonstrator in the Chemistry Department of McGill University, Montreal. Here he worked with Professor Sir Ernest Rutherford on problems of radioactivity. Together they published a series of papers on radioactivity and concluded that it was a phenomenon involving atomic disintegration with the formation of new kinds of matter. They also investigated the gaseous emanation of radium.

From 1904 to 1914 Soddy was lecturer in physical chemistry and radioactivity in the University of Glasgow. Here he did much practical chemical work on radioactive materials. During this period he evolved the so-called “Displacement Law”, namely that emission of an alpha-particle from an element causes that element to move back two places in the Periodic Table. His peak was reached in 1913 with his formulation of the concept of isotopes, which stated that certain elements exist in two or more forms which have different atomic weights but which are indistinguishable chemically.

Visit the official web site of the Nobel Foundation to read more about Frederick Soddy.

 Excerpted with permission, www.nobelprize.org