Tennessine's Wild Ride To The Periodic Table There are rare chemical elements, and then there is tennessine. Only a couple dozen atoms of the stuff have ever existed. For the 150th anniversary of the periodic table, NPR science correspondent Joe Palca shares the convoluted story of one of the latest elements to be added.

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Tennessine's Wild Ride To The Periodic Table

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Tennessine's Wild Ride To The Periodic Table

Tennessine's Wild Ride To The Periodic Table

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VIET LE, BYLINE: Hey there. I'm Viet Le, editor of SHORT WAVE. If you've been listening over the past couple of weeks, you know that there's been a big monthlong competition here at NPR to see which podcast can drive the most donations. And this is the very last day to help us out - the very last day. I'm not actually that into contests and am a huge procrastinator, but if competitions and deadlines motivate you, that's great. Go to donate.npr.org/short to find your local NPR station and give. Again, that's donate.npr.org/short. OK, here's the show.

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MADDIE SOFIA, HOST:

You're listening to SHORT WAVE from NPR. Maddie Sofia here. It's the 150th anniversary of the periodic table of elements, and we have been celebrating by highlighting some of our favorite elements. We did helium. We did aluminum. We did iridium. And NPR science correspondent Joe Palca is going to bring it home today with one of the rarest elements.

JOE PALCA, BYLINE: That's right, Maddie. I've got for you tennessine. It's one of the last elements to be discovered, and only a couple dozen atoms of the stuff have ever existed.

SOFIA: OK, so tennessine - Ts on the periodic table, atomic number 117. It's super rare. What else do we know about it?

PALCA: Truth is not much. (Laughter) There - it's very rare. They only had a few to discover, and they didn't last very long. But they do know it lies on the outer edges of the periodic table, and it's one of a group of unstable synthetic elements that - poof - go away in a quick blink of an eye.

And there's one other thing you should know to understanding how this element came to be.

SOFIA: OK, what?

PALCA: Tennessine is a synthetic element. Basically, unlike a lot of elements, you can't find it in nature. You have to make it. And to make it, you need to fuse together two existing elements.

SOFIA: So it's like two elements get together and make a new baby element.

PALCA: Well, if you're talking about a mommy element and a daddy element and they love each other very much, I'd say no. It's more like the two get together and form a partnership or fusion.

SOFIA: OK.

PALCA: In this case, it's berkelium and calcium. But, Maddie, getting them into the same room together was a bit of an ordeal.

SOFIA: So today on the show, tennessine's wild ride to the periodic table. We're going to Tennessee, and we're going to Russia.

PALCA: But first, Maddie, we're going to get stuck in customs a couple times.

SOFIA: Sounds about right.

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SOFIA: OK, Joe, where do we start this journey?

PALCA: We start in Tennessee.

SOFIA: I guess we are talking about tennessine, after all.

PALCA: Yeah. Actually, that's where the name comes from. So Oak Ridge National Lab is in Tennessee, and it's the only place in the world where you can get enough berkelium to make tennessine. And berkelium is also a synthetic element, and it takes several months in a special reactor at Oak Ridge to make it.

SOFIA: Joe, what is berkelium used for?

PALCA: Well, commercially, it ain't used for anything. But in this case, it's being used to create a new element by combining it with calcium. But there's only a few places in the world where they could do that, and one of them is in Russia.

SOFIA: So we're getting on a plane, Joe?

PALCA: That is correct, Maddie. And we have a guide for our journey. He was one of the key researchers on the quest to create tennessine. And I'll let him introduce himself.

KRZYSZTOF P RYKACZEWSKI: (Laughter) This is a difficult part of the interview - Krzysztof P. Rykaczewski.

PALCA: Rykaczewski was part of the team that would measure the outcome of the experiment and see whether they were able to detect the creation of tennessine. So the team in Tennessee packed up the highly radioactive berkelium in specially shielded containers. A shipping company then sent the containers up to New York's JFK Airport. And there, they were loaded onto a plane for Moscow. But there was a problem.

RYKACZEWSKI: Somebody in this final (ph), you know, shipping company was so excited that she forgot to give the papers to the captain. It flew to Moscow but without the shipping papers.

SOFIA: So the radioactive berkelium flew all the way to Moscow without shipping papers.

PALCA: That's right. And when the plane landed, customs agents looked at this - containers festooned with hazardous material of, you know, dangerous radioactivity and no paperwork describing the contents.

RYKACZEWSKI: You can imagine that you have the big package marked with poison (ph). So I am not surprised what the Russians did. They immediately sent it back with the first plane or the same plane to New York.

SOFIA: (Laughter) I get it.

PALCA: Yeah, right?

SOFIA: I mean, I kind of get it.

PALCA: OK, so back the package goes to JFK. And this time, they get it back on board. And, for sure, they've got the papers onboard, and they send it back to Russia.

SOFIA: Here we go.

PALCA: OK, except there was another problem.

SOFIA: What do you mean? What was wrong with it this time?

PALCA: Well, it seems that even though the papers were in order, the Russian customs agents weren't satisfied. I think maybe they were a little annoyed with the fact that they were surprised by the first shipment.

RYKACZEWSKI: They introduce a new rule. That's fine - the papers, but we would like to have such papers by fax when the plane is starting so we are better prepared to receive the cargo. So what they did - they sent it back. This is the fourth flight, yeah?

SOFIA: OK, so this radioactive material is just flying back-and-forth, back-and-forth between New York and Moscow.

PALCA: Exactly. And meanwhile, the clock is ticking here, Maddie...

SOFIA: Right.

PALCA: ...Because this berkelium has a half-life of 327 days or thereabouts, which means it's decaying while it's sitting in storage going back-and-forth, or sitting on an airplane.

SOFIA: Well, I feel like this is so representative of how science is actually done. It's, like, a huge project. They're really excited. And then it's just a logistical nightmare that leads to a lot of stress.

PALCA: Yep, sounds familiar, doesn't it?

SOFIA: Yeah.

PALCA: And on the fifth transatlantic flight, the cargo finally made it into the country. It was then put on another plane to the Joint Institute for Nuclear Research in Dubna.

RYKACZEWSKI: And then in the Research Institute for Atomic Reactors, Russian chemists started to deposit the material on the titanium plates.

PALCA: And that's when the berkelium finally got to meet the calcium that would turn it into tennessine.

SOFIA: So, OK, let's talk about the science. What did the researchers do once they finally had the berkelium and the calcium in the same lab?

PALCA: So for months, they used a special accelerator kind of machine called a cyclotron to fire calcium atoms at the berkelium target.

SOFIA: So they literally shoot calcium at berkelium.

PALCA: That is exactly what happens. They use a cyclotron to pummel this target with calcium, hoping that the calcium and the berkelium will fuse to form tennessine.

SOFIA: And what were they actually hoping to see happen? Like, how do you know if you're successful?

PALCA: Well, Rykaczewski says they knew they weren't going to see tennessine directly. I mean, it's not like these things fly off with a little tag on them saying, hey, everyone, I'm tennessine, thanks for making me. But they come off, and they show up in a sensor near the target that shows where there's a pulse of energy. And this pulse of energy comes in a particular pattern, which they were actually able to predict in advance. And that's what told them they were getting the tennessine.

SOFIA: So they kind of knew what they were looking for.

PALCA: Right.

RYKACZEWSKI: And everything was nicely fitting to the picture that we observe six decays of element 117 (ph).

SOFIA: Isn't it nice when it works like that?

PALCA: Well, yes. And it wasn't - I mean, it might not have. I mean, obviously, you know, months of firing, and six atoms - it wasn't, like, a slam dunk. They weren't sure they were going to get this, but they did.

RYKACZEWSKI: It could go wrong in many ways, yeah, but it went well. So the picture was very coherent, I would say. And we claim a discovery of a new element, and then additional experiments that proved we are right.

SOFIA: I feel like this is kind of amazing - like, shooting elements at other elements, making new elements. I'm curious, though, like, why these scientists are going through such great lengths to find these very rare and fleeting elements like tennessine.

PALCA: Well, I think it's really to get a more complete picture of the way atoms are created. I mean, there's nothing handed down from on high about the periodic table. It was a way of grouping chemical elements. And according to the groupings that they had, there was a row at the bottom of the table that wasn't filled in...

SOFIA: Right.

PALCA: ...Which suggested that if there were other elements that were in the columns that were missing in the row, well, maybe we could make them. So that's what they did.

SOFIA: So these synthetic elements that we're discovering and finding and making, it's more about understanding how elements come to be and scientific inquiry and, like, filling out the periodic table.

PALCA: Right. I mean, I think there's just this question that it's like an itch, you know? It should be there. We better find it. And the other thing is I asked Rykaczewski why he's still looking.

RYKACZEWSKI: Are we searching for new elements? Yes. It's fun, you know? It's really great thing to discover a new element (laughter). And we are in the process of searching for element 119, and we are preparing the search for element 120.

SOFIA: So we are not done filling in the periodic table.

PALCA: Doesn't seem like it.

SOFIA: All right, Joe Palca, thank you so much for helping us celebrate the periodic table's birthday by taking us on this tennessine journey.

PALCA: You're welcome.

SOFIA: This episode was produced by Brit Hanson, edited by Andrea Kissack and fact-checked by Emily Vaughn. Thanks for listening to SHORT WAVE from NPR.

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