Frederick Soddy: Radioactivity, Isotopes, Social Responsibility of Scientists and the Environment

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In 1913, Frederick Soddy proposed the concept that a radioactive element can have more than one atomic weight and occupy the same place (isotope, from the Greek meaning “same place”) in the periodic table although the chemical properties are identical. Ironically, after receiving the Nobel Prize in Chemistry (1921), he abandoned chemistry and shifted his interest to politics, the global monetary system, debt, the environment, and the social implications and responsibilities of science and scientists.

By George B. Kauffman

Amid the kerfuffle caused by John Hutson’s misguided attempts to introduce nuclear power plants into Fresno County despite the recent Fukushima nuclear disaster, I thought Community Alliance readers would appreciate information about radioactivity, radioisotopes and related matters.

The important discoveries in radioactivity that occurred between the end of the 19th century and the second decade of the 20th century were equally divided between chemists and physicists. Soddy was one of the most prominent trail blazers among the chemists. Born in Eastbourne, England, on September 2, 1877, he studied at Eastbourne College (1892–1894), Aberystwyth College of Wales (1894–1895) and Merton College, Oxford University (1895–1898).

After two years of independent research at Oxford, in 1900 Soddy became demonstrator in chemistry at McGill University in Montréal, Quebec, where, beginning in October 1901, he worked on radioactivity for 18 months with New Zealand–born British physicist Ernest Rutherford, the father of nuclear physics and future (1908) Nobel Chemistry laureate “for his investigation into the disintegration of the elements, and the chemistry of radioactive substances.” Amused by the award’s irony, Rutherford quipped, “I have dealt with many different transformations with various periods of time, but the quickest I have met was my own transformation in one moment from a physicist to a chemist.”

Rutherford had earlier shown that radioactive elements spontaneously emit rays that he called alpha, beta and gamma. Alpha rays were later found to be nuclei of the element helium, beta particles were found to be electrons and gamma rays were found to be high-energy electromagnetic radiation.

Alpha radiation doesn’t travel far, can be stopped by a thin sheet of paper, but is damaging in this short distance. Beta radiation goes further than alpha but is less damaging. Gamma radiation can pass through lead but isn’t very damaging; in fact, it can be used to sterilize medical equipment, to see inside a patient (radioactive “tagging”) and to treat some kinds of cancer.
Radiation can’t travel far so it’s not a risk over long distances, but when radioactive dust contaminates or lands on something, it can be a risk over long distances.

Following a radiological or nuclear event, radioactive iodine may be released into the air and breathed into the lungs. Radioactive iodine may also enter the body through food or drink (“internal contamination”) and be absorbed by and injure the thyroid gland. Pregnant women and infants are mostly at risk. Because non-radioactive potassium iodide (KI) blocks radioactive iodine from the thyroid, it helps protect it from injury. Local public health or emergency management officials will tell us if KI should be taken, but some panic-stricken people who distrust the government (sometimes not without reason) bought up supplies of KI.

During those early years, radioactivity was poorly understood by scientists, but Soddy and Rutherford realized that this anomalous phenomenon was caused by decay into other elements with the simultaneous emission of alpha, beta, and gamma radiation. They published a series of historic articles proposing that the atoms were breaking apart and forming new kinds of matter. They had succeeded in accomplishing the dream of the ancient alchemists—the transmutation of one element into another! They advanced a disintegration theory of radioactivity explaining how this process occurred. Because Rutherford was the older and more established member of the team and Soddy erroneously considered a junior partner, Rutherford garnered most of the credit for their work.

In 1903, Soddy left Canada to work at University College, London, with Scottish chemist Sir William Ramsay, who won the Nobel Chemistry Prize in 1904 for his discovery of the inert gases of the atmosphere (neon, argon, krypton, xenon and radon) and their place in the periodic table. We’ve all heard of the first of these elements for its use in electric signs and the last for its possible lurking in our basements waiting to attack our lungs with cancer.

The inert gases have since been redubbed “noble gases” because in 1962 British chemist Neil Bartlett at the University of British Columbia, Vancouver, found they do react with other elements to form compounds. I learned of this momentous discovery at a workshop in Columbus, Ohio, but, indoctrinated with the dogma that the gases were inert, I believed the announcement was a joke. (So much for my scientific open mind!) I thought Bartlett should have received the Nobel Prize, but he unfortunately died in 2008, and prizes are not awarded posthumously.

Soddy and Ramsay used a spectroscope to show conclusively that helium is produced from the disintegration of radium—the first experimental proof of the natural transmutation of elements proposed earlier by Soddy and Rutherford. The spectroscope is an instrument containing a prism that splits up light forming a rainbow-like pattern that can be used as a “fingerprint” to detect the presence of chemical substances. In a most unexpected discovery, English astronomer Norman Lockyer in 1868 had trained his telescopic spectroscope on the sun and found a yellow line that he couldn’t explain as due to any known element. He suggested that this line was caused by an unknown solar element, which he called helium after the Greek word helios meaning “sun.” He had no idea that the element was a gas so he chose the neuter Latin suffix “-ium,” customarily used for metals, and we’re stuck with this misnomer.

Frederick Soddy (1877-1956). (Courtesy, the Nobel Foundation).

From 1904 to 1914, Soddy served as a lecturer at Glasgow University, Scotland, where he proposed that some elements might exist in two or more forms with different atomic weights but identical chemical properties. Because they possess the same atomic number and occupy the same place in the periodic table, he introduced the term isotope (from the Greek, meaning “same place”). This was long before the British rock fusion band and Albuquerque baseball team of the same name! This concept earned him the Nobel Chemistry Prize in 1921. Within a single month in 1914, he and three other groups proved this concept experimentally by showing that lead produced by disintegration of radium differed in atomic weight from ordinary natural lead.

In 1908, Soddy married Winifred Beilby. They had no children; Soddy thought that his work with radioactivity had rendered him sterile. From 1914 to 1919, he was a professor of chemistry at Aberdeen University, Scotland, but his research was hampered by war work.

Soddy’s work and essays popularizing a new understanding of radioactivity furnished the primary inspiration for H.G. Wells’ book, The World Set Free (1914), which featured atomic bombs dropped from biplanes in a war set many years in the future. This novel, also known as The Last War, imagined a peaceful world emerging from the chaos.

When Soddy became Lee’s professor of chemistry at Oxford University (1919–1936), his interest shifted to the social implications of science, and he became a controversial critic of misused energy sources, global debt, monetary theory, economics, business, finance, sociology, politics and the environment.

Soddy was driven by his perception of the need to work for the improvement of the lot of humankind and his feeling that efforts must be made to direct the fruits of science to beneficent uses to achieve this goal. He wrote: “It is modern science, which has made the modern world great, with a greatness that the illustrious epochs of history cannot match.” His foreword to Sir Daniel Hall’s book, The Frustration of Science, is a classic call for responsibility in science.

Soddy was profoundly disturbed by World War I and enraged by the death of young English physicist Henry Gwyn Jeffreys Moseley, whose concept of atomic numbers revolutionized the periodic table. Moseley was killed by a Turkish sniper’s bullet on August 10, 1915, during the ill-fated Gallipoli invasion. According to Isaac Asimov, “In view of what he might still have accomplished…his death might well have been the most costly single death of the War to mankind generally.” Asimov also speculated that if he had not been killed, Moseley might have been awarded the Nobel Physics Prize in 1916.

Because Soddy’s research pointed to the vast potential for nuclear energy, he realized earlier than most persons the theoretical possibility of this energy source. A true visionary, in his book, Wealth, Virtual Wealth, and Debt, he asked the question: “What sort of a world it would be if atomic energy ever became available.”

He immediately answered, “If the discovery were made tomorrow, there is not a nation that would not throw itself heart and soul into the task of applying it to war, just as they are now doing in the case of the newly developed chemical weapons of poison-gas warfare…If [it] were to come under existing economic conditions, it would mean the reductio ad absurdum of scientific civilization, a swift annihilation instead of a lingering collapse.”

In 1936, Soddy took early retirement following the death of his wife that year. His declining years were marked by unhappiness. He felt, with some justification, that his later contributions were not adequately recognized. He died at Brighton, England, on September 22, 1956, at the age of 79. Soddyite, a radioactive uranium mineral, and a crater on the far side of the moon are named in his honor.

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George B. Kauffman, Ph.D., chemistry professor emeritus at California State University, Fresno and Guggenheim Fellow, is a recipient of the American Chemical Society’s George C. Pimentel Award in Chemical Education, the Helen M. Free Award for Public Outreach and the Award for Research at an Undergraduate Institution. This year he was elected an ACS Fellow.