Frederick Soddy

English chemist

• Born: September 2, 1877; Eastbourne, England
• Died: September 22, 1956; Brighton, England

Frederick Soddy received a Nobel Prize in Chemistry for revolutionizing the understanding of the nature of radioactive particles, specifically by proposing the existence of isotopes—atoms of the same chemical element that have the same atomic number but different radioactive properties and atomic weights. His theory ran counter to the long-held assumption that all atoms of a particular element were identical in size and atomic weight.

Primary field: Chemistry

Specialty: Atomic and molecular physics

Early Life

Born in Eastbourne, a resort town along the coast of the English Channel, Frederick Soddy was the youngest of seven children. His mother, Hanna Green, died before he was two years old; his father, Benjamin Soddy, a successful corn and seed merchant, was instrumental in his early development. Soddy’s father taught him about economic realities and social classes, the restrictions placed on those with a rural background or lacking education, and the importance of technology in achieving social and economic advancement. Soddy, however, showed an early aptitude not for economics but for hard sciences.

At Eastbourne College, a prestigious boarding school in Sussex, Soddy, at age seventeen, coauthored with the school’s science headmaster a groundbreaking paper on chemical reactions involving carbon dioxide. Buoyed by this success and determined to pursue a career in theoretical chemistry, but concerned about his own readiness for the rigors of university study, Soddy enrolled in a year of preparatory studies at University College of Wales at Aberystwyth. He then secured a science scholarship to Merton College, Oxford.

Soddy began his study at Merton in 1896. Although socially awkward, he distinguished himself for his thoroughness and his probing intellect. He passed the chemistry examination in 1898 and achieved a first-class rating in the School of Natural Sciences. For the next two years, Soddy remained at Oxford, but he grew restless over the university’s lack of advanced chemistry research facilities. In 1900, he decided to pursue a position in chemistry at the richly endowed McGill University in Montreal, Canada.

At McGill, Soddy worked in first-rate facilities under the direction of one of the early century’s most promising theoretical chemists, Ernest Rutherford, whose pioneering work was in the new field of radioactivity. Over the next two years, Soddy and Rutherford published a series of highly regarded papers theorizing about the phenomena of nuclear decay and the disintegration of highly unstable radioactive elements into other radioactive elements.

Life’s Work

Upon returning to England in 1902, Soddy went to work at University College, London with Sir William Ramsay, a Nobel Prize winner who had studied the gaseous products of radioactive decay and had first discovered the noble gases. As Soddy began what would become his defining work, scientists wanted to determine the chemical identification of the elements produced in radioactive decay. They had begun to identify a mystifying variety of apparently new elements produced by such processes, which challenged the systematic premise of the periodic table, an ingenious arrangement devised barely fifty years earlier in which physical and chemical qualities in elements were conceived as functions of their atomic weight. Researchers wanted to know whether these apparently new elements actually were new, and, if they were, how they would fit in the limited spaces available in the periodic table. Together, Soddy and Ramsay demonstrated that the radioactive decay of radium bromide produces helium. Although Ramsay’s international credibility was subsequently undermined by his public endorsement of an eccentric scheme to extract gold from seawater, Soddy avoided such distractions and accepted a post at the University of Glasgow in Scotland in 1904.

During the next ten years at Glasgow, Soddy developed his revolutionary radioactive displacement law, which drew on his experimental work showing that uranium decays into radium. Soddy’s pioneering work first describes the transformations that occur when a decaying radioactive element loses either its alpha or beta particles, then theorizes that the loss of an alpha particle by an element with an even number on the periodic table causes a dramatic but predictable shift in that element’s atomic weight (a decrease of four) and its atomic number (a decrease of two). Thus, alpha decay creates an element that would be two places to the left in the standard periodic table. Beta emission revealed a similarly predictable shift to one place higher. What were being created by radioactive decay were not new elements but rather variations of elements already charted.

Soddy’s results led to a radical premise, which he published in 1913: two or more elements might be identical chemically and occupy the same space in the periodic table but still differ in their atomic weight. He would receive the Nobel Prize in Chemistry in 1921 for this revolutionary work. Soddy described the elements being produced as isotopes, a coinage of Scottish doctor and family friend Margaret Todd; the term draws from the Greek and means “the same place.”

In 1914, Soddy left Glasgow to accept the chair in chemistry at the University of Aberdeen, where he continued his work, specifically in the extraction of lead from the radioactive ore thorite. During World War I, he assisted in research work to extract ethylene, a potent anesthetic, from coal gas. After the war, Soddy accepted an endowed chair in chemistry at Oxford, where it was anticipated he would lead Oxford’s efforts to develop a research facility with an international reach. That was not to be, however. Soddy was distant and prickly with his students, quarreled with faculty, found the administration unimaginative, and quickly alienated the facility from significant funding.

Soddy then turned from research work to studies in social and economic philosophy, working on an ambitious agenda for improving humanity by the unconditional embrace of technology. Boldly, he applied the quantum principles of energy and elemental transformation to the flow and distribution of money, drawing on arguments he had heard years before from his wealthy father. After he took early retirement from Oxford in 1936 at age fifty-nine, shortly after the death of his beloved wife, Soddy emerged as a vigorous proponent of sweeping iconoclastic political, economic, and social reforms. Indeed, after World War II, Soddy, like many other scientists, became alarmed by atomic bombs and the contributions his earlier work had inadvertently made to their development. He also was keenly aware that his work had helped H. G. Wells write his 1914 science-fiction classic World Set Free, which first described atomic-powered bombs. Soddy began to advocate for the banning of nuclear weapons and the use of nuclear energy for peaceful purposes only.

Soddy died on September 22, 1956, in Brighton, England. He is remembered not only for his groundbreaking theoretical work but also for his considerable body of economic writings and his unflagging dedication to social activism.

Impact

Positioned historically at the threshold of what would become the atomic age, and then the nuclear age, Soddy belongs to the generation that first clarified in the spirit of scientific investigation the bewildering implications of the new field of radioactivity and charted for the first time the eccentric patterns of a subatomic world. Long after his hypothesis describing isotopes had become a scientific commonplace, Soddy, much like his far-better-known contemporaries such as Bertrand Russell, Linus Pauling, J. Robert Oppenheimer, and Albert Einstein, found his public voice amid the anxieties of the post–Hiroshima and Nagasaki nuclear era. In his mind, problems such as economic inequity and political strife could be solved by the application of scientific principles of order and design and the embrace of the promise, rather than the horrors, of technology. With visionary energy and a moral compassion that derived from his profound appreciation of the symmetry and purposeful organization of the subatomic world, Soddy extended the reach of twentieth-century science by applying its most complex principles as metaphors for compassionate social and political evolution.

Bibliography

Brown, G. I. Invisible Rays: A History of Radioactivity. Phoenix Mills: Sutton, 2002. Print. A concise introduction to the science behind Soddy’s hypotheses, beginning more than two centuries before his work.

Malley, Marjorie C. Radioactivity: A History of a Mysterious Science. New York: Oxford UP, 2011. Print. Includes a section on Rutherford and Soddy’s collaboration within the context of the larger history of radioactivity.

Merricks, Linda. The World Made New: Frederick Soddy, Science, Politics, and Environment. New York: Oxford UP, 1996. Print. A biography that includes an analysis of Soddy’s second career in economic and political philosophy and clarifies his understanding of the role of scientists in a postwar world.