Periodic Table Pioneer

You may have noticed a periodic table in your science classroom or in a recent issue of Science World. If you take a closer look at the table, you’ll see 118 neatly organized elements. They are the building blocks that make up all matter in the universe.

Russian chemist Dmitri Mendeleev developed the first version of the periodic table in 1869. Back then, scientists knew of only 63 elements. More continued to be discovered. By the late 1930s, scientists had identified all 92 elements that occur naturally on Earth. But researchers wondered: Could they create synthetic, or lab-made, elements that had never been seen before? It turned out they could.

James Harris, a chemist at Lawrence Berkeley National Laboratory in California, played a pivotal role in this push to expand the periodic table. In the late 1960s, he and his colleagues helped create two new additions to the table—making Harris the first Black scientist recognized as the co-discoverer of an element.

You may have noticed a periodic table in your science classroom or in an issue of Science World. Take a closer look at the table, and you’ll see 118 neatly organized elements. These building blocks make up all matter in the universe.

The first periodic table appeared in 1869. Russian chemist Dmitri Mendeleev developed it. Back then, scientists knew of only 63 elements. More continued to be discovered. On Earth, 92 elements occur naturally. By the late 1930s, scientists had identified all of them. But researchers wondered if they could create synthetic elements in a lab. Such elements had never been seen before. It turned out they could.

James Harris played a key role in this push to expand the periodic table. He was a chemist at Lawrence Berkeley National Laboratory in California. In the late 1960s, he and his colleagues helped create two new additions to the table. Harris became the first Black scientist recognized as the co-discoverer of an element.

Harris was born in Texas in 1932. His mom worked in a school cafeteria. His dad, a farmer, died when Harris was young. When he was 12, Harris moved to California to live with his aunt. A teacher there encouraged him to take a chemistry class. He loved it!

Harris’s other love was music. He played the trumpet and French horn in school bands and received a scholarship to study music at Huston-Tillotson College—a historically Black institution in Texas. But after performing on the road briefly during college, he decided that a musician’s life wasn’t for him and shifted his focus to science.

In 1953, Harris graduated from Huston-Tillotson with a degree in chemistry. After two years in the Army, he started applying for laboratory jobs. The process was a struggle, as Harris frequently experienced racism. Racial discrimination was widespread in the 1950s, and Black Americans were often denied equal access to education, employment, and housing. In a 1973 interview with Ebony magazine, Harris recalled that at some workplaces, people assumed he was applying to be a janitor rather than a scientist. In 1955, he was hired as a chemist at Tracerlab, a California company that made equipment for detecting radiation—high-energy particles and rays.

In 1960, Harris got a new job at the government-run Berkeley Lab. In his early years there, he studied radioactive decay. During this process, unstable atoms—the smallest units of an element—break down, releasing radiation. Later, Harris joined a Berkeley group working toward the goal of producing new elements.

Harris was born in Texas in 1932. His mom worked in a school cafeteria. His dad was a farmer, but he died when Harris was young. When Harris was 12, he moved to California to live with his aunt. A teacher there encouraged him to take a chemistry class. He loved it!

Harris’s other love was music. He played the trumpet and French horn in school bands. He also received a scholarship to study music at Huston-Tillotson College, a historically Black institution in Texas. During college, Harris performed on the road briefly. But he decided that a musician’s life wasn’t for him. So he shifted his focus to science.

In 1953, Harris graduated from Huston-Tillotson with a degree in chemistry. He spent two years in the Army. Then he started to apply for laboratory jobs. This was a struggle, because Harris experienced racism over and over. Racial discrimination was widespread in the 1950s. Black Americans were often denied equal access to education, employment, and housing. In a 1973 interview with Ebony magazine, Harris recalled his experience. He was applying to be a scientist. But at some workplaces, people assumed he was applying to be a janitor. In 1955, he was hired as a chemist at Tracerlab. This California company made equipment for detecting high-energy particles and rays known as radiation.

In 1960, Harris got a new job at the government-run Berkeley Lab. In his early years there, he studied radioactive decay. During this process, unstable atoms break down and release radiation. Atoms are the smallest units of an element. Later Harris joined a Berkeley group with another goal. They were working to produce new elements.

Harris’s group used a particle accelerator—or atom-smashing machine—to fire high-speed particles at samples of known elements. The scientists hoped some particles would combine with atoms in the target sample and form a new element through a nuclear reaction.

Harris specialized in preparing targets for the accelerator. For his most famous experiment, he applied a thin layer of the previously discovered synthetic element 98, named californium (Cf), onto a metal foil. At the time, only a tiny amount of californium had ever been produced—and Harris was working with almost all of it. These precious samples tended to contain lead (Pb) and other unwanted elements. The scientists needed to be sure that new substances created in the accelerator formed through a reaction with californium alone and not some other element. Removing the impurities was critical, but it wasn’t easy. “That separation is notoriously hard to do,” says Kristen Frederick-Frost. She’s a historian and curator of medicine and science at the Smithsonian Institution who has researched Harris’s life and career.

Luckily, Harris was exceptionally skilled at purifying his samples. He developed a 22-step process to create what his group leader called “the best target we have ever had.” In 1969, Harris and his teammates successfully created element 104—now known as rutherfordium (Rf). Element 105, now called dubnium (Db), followed in 1970. A lab in Russia challenged Berkeley’s claim of being first to create these elements. In 1997, the organization in charge of element names split credit between the two teams.

Harris’s group used an atom-smashing machine called a particle accelerator. It fires high-speed particles at samples of known elements. The scientists hoped some particles would combine with atoms in the target sample. They might form a new element through a nuclear reaction.

Harris prepared targets for the accelerator. Synthetic element 98 had already been discovered. It was named californium (Cf). For his most famous experiment, Harris applied a thin layer of californium onto a metal foil. Only a tiny amount of californium had ever been produced. Harris was working with almost all of it. These precious samples tended to contain lead (Pb) and other unwanted elements. Scientists wanted new substances to form in the accelerator through a reaction with californium alone. So they needed to remove the other elements. But this wasn’t easy. “That separation is notoriously hard to do,” says Kristen Frederick-Frost. She’s a historian and curator of medicine and science at the Smithsonian Institution. She has researched Harris’s life and career.

But Harris was an expert at purifying his samples. He developed a 22-step process to create a target. His group leader called it “the best target we have ever had.” In 1969, Harris and his teammates successfully created element 104. It is now called rutherfordium (Rf). Element 105 followed in 1970. It’s known as dubnium (Db). A lab in Russia claimed to be the first to create these elements. In 1997, the organization in charge of element names split credit between the two teams.