Hank Green: If a young chemist created a dream career to-do list, it might read something like this: Expand the periodic table. Advise the president. Have an element named after you. Win a Nobel prize, and then turn lead into gold. Chemistry and physics superstar Glenn Seaborg did all of that in his lifetime, except that he actually advised ten presidents, Truman through Clinton, and only transmuted a tiny bit of gold.

(SciShow Intro plays)

Hank: Glenn Seaborg was born in 1912 and spent most of his life in California, earning a Chemistry doctorate from Berkeley and joining the faculty when he was just 27 years old. And the heart of Seaborg's life work centered on synthesizing and studying elements. He and his colleagues discovered, by which I mean created, ten transuranium elements and lots and lots of isotopes frequently used today in medicine, industry, and nuclear power. Yes, he created elements. Have a look at your periodic table, if you have one. If you don't, go to dftba.com and buy the CrashCourse Chemistry giant periodic table, 39 inches across, it's amazing. Then, tape it up above your bed so you can look at it. Technically, all of the elements through atomic number 98 occur naturally on Earth, but nine of those occur so rarely and in such small amounts that they were actually synthesized in a lab before they were ever found in nature. Seaborg helped discover/create most of these. And so far, we also have 20 elements that are truly synthetic, only ever created in a lab. So, how do you make an element?

You probably remember from Chemistry class that an element's atomic number is the number of protons in its nucleus. Well, you can create a new element by adding or removing protons from an existing element's nucleus, thus turning it into something new. Seaborg's lab wasn't the first to do this, but he really nailed the technique. Of course, it's not like clicking one LEGO onto another, it requires particle accelerators and nuclear reactors and a lot of energy, but eventually, if you keep bombarding say, uranium, atomic number of 92, with alpha particles made up of two neutrons and two protons, you can get that uranium to accept those particles and turn into Plutonium, with an atomic number of 94, and that is exactly what Seaborg and his team did in 1940 at his Berkeley lab. He made isotopes this way as well, those are just atoms with the same number of protons but different numbers of neutrons. Plutonium, as an example, has 20 identifiable isotopes, and probably the most important one that Seaborg made was Plutonium-239, because it, along with Uranium-235, can fuel nuclear plants and atomic bombs. 

Once word got out that Seaborg had devised Plutonium-239 as a potential source for nuclear energy, Washington suddenly got mighty interested in him and his work. When the US became involved in World War II, Seaborg was recruited as the Plutonium expert on the Manhattan project, he was just 30 years old at the time. On his way to the University of Chicago, he married his sweetie, Helen Griggs, who was at the time, Secretary to Nobel Laureate physicist Dr. Ernest Lawrence, and the two remained together until his death, raising six kids along the way, just in case you were thinking he only ever did physics and chemistry. In Chicago, Seaborg worked on figuring out the most efficient processes for producing and isolating enough Plutonium-239 to fuel a nuclear reaction. In the end, the government used both Uranium in the bomb used on Hiroshima, and Plutonium, which powered the bomb dropped on Nagasaki.

In 1951, Seaborg and his predecessor at the Berkeley lab, Edwin McMillan, were awarded the Nobel Prize in Chemistry for their achievements in creating artificial elements. But Seaborg shook things up even more when he realized in 1945 in his search for elements 95 and 96 that many of the heavier elements were essentially in the wrong place on the periodic table. Instead, based on their expected properties, elements heavier than 89 belonged under the rare earths, in the lanthinide series. He called this new addition the actinide series, and it resulted in the last major change to the periodic table. It should be noted that we now call those things the lanthanoids and the actinoids, not lanthinides and actinides. I don't know why they made that change, but they did.

Apparently, unsettled by the effectiveness of the nuclear weapons that were derived from his work, in 1961, Seaborg became the chair of the US Atomic Energy Commission. He remained at this post for the next ten years and became deeply involved in nuclear regulatory policy and arms control. He also played a key role in ushering in the Limited Test Ban Treaty that prohibited all above-ground nuclear test detonations. Though wary of its use in weapons, Seaborg saw great promise in the friendlier applications of nuclear energy, saying, "I had helped create the most destructive man-made force ever known, but I was convinced that the atom had even greater potential for peaceful uses."

Seaborg died in 1999 at the age of 86, just a few years after the newly created element 106 was christened seaborgium in his honor, a testament to his supreme chops, it was the first element named after a still living person.

Thank you for watching this SciShow Dose, especially to you Subbable subscribers, without whom we could not do this. To learn how you can subscribe and also get awesome perks like a personalized lab coat, go to subbable.com and don't forget to go to youtube.com/scishow and subscribe.

(SciShow Endscreen plays)