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Contributor: Elephango Editors. Lesson ID: 12491
How were radioactive elements discovered and named? Uncover the scientists, stories, and surprises behind the periodic table’s most powerful additions.
The Race to the Unknown
Imagine working in a lab where every experiment might lead to the discovery of something no human has ever seen—an entirely new element! Now, imagine you get to name it.
That was the reality for scientists in the early 20th century. As technology advanced and curiosity grew, chemists and physicists began uncovering—and even creating—elements that didn't exist in nature.
Some were so unstable they vanished in seconds. Others changed the world forever.
Step back in time and uncover how radioactive elements were discovered, created, and named.
The Early Discoveries
Radioactivity became a major scientific focus in the late 1800s.
In 1896, Henri Becquerel accidentally discovered that uranium gave off invisible energy that could fog photographic film. Just a few years later, Marie and Pierre Curie expanded on his work, discovering two new radioactive elements: polonium and radium.
Marie named polonium after her home country, Poland. Their groundbreaking research helped define the concept of radioactivity.
From Natural to Synthetic: Building New Elements
After the discovery of uranium (atomic number 92), scientists wondered: Could there be elements beyond it?
In 1940, teams of researchers at the Lawrence Berkeley National Laboratory began using particle accelerators to bombard atomic nuclei with neutrons and protons. The result? The first synthetic elements: man-made atoms not found in nature.
Neptunium (93) and Plutonium (94) were created by modifying uranium atoms.
Their names reflect their position after uranium, which is named after the planet Uranus. Neptunium and Plutonium were named for Neptune and Pluto.
These discoveries occurred during the early 1940s, concurrent with the events of World War II, when the power of radioactive elements was being explored for both scientific and military applications.
Seaborg and the Surge of the 1940s–50s
One of the most influential nuclear chemists of this period was Glenn Seaborg, who helped discover several elements.
Americium (named for the Americas)
Curium (after Marie and Pierre Curie)
Berkelium and Californium (named for the city of Berkeley and the state of California)
After the hydrogen bomb test in 1952, scientists discovered einsteinium and fermium, which had formed during the explosion.
Later discoveries, such as mendelevium (named for Dmitri Mendeleev, the father of the periodic table) and nobelium (named for Alfred Nobel, founder of the Nobel Prize), continued the trend.
Patterns in Naming
As the periodic table expanded, a trend emerged: new elements were often named after the following.
Scientists (e.g., rutherfordium, seaborgium, lawrencium)
Places (e.g., dubnium, berkelium, californium)
Concepts or celestial bodies (e.g., neptunium, plutonium)
Most of these discoveries were made by tracking radiation and measuring half-lives, or by smashing particles together in high-energy laboratories. As elements became heavier, they also became more unstable—some exist for only fractions of a second before decaying.
Why Fewer New Elements Are Found Today
There’s a physical limit to how large atoms can be. Past a certain point, their nuclei become too unstable to last.
That’s why the pace of discovery has slowed down. New elements today are often very short-lived and extremely difficult to detect.
Still, each new discovery deepens our understanding of atomic structure, and each name tells a story of scientific achievement.
You’ve now learned how radioactive elements were uncovered, named, and even created—and how the search for new elements reshaped science in the 20th century.
Head to the Got It? section to see what you can recall and apply in an interactive challenge!
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