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Element 105, Dubnium,...
...was the shortest video we made, at 45 seconds.
I know very little about Dubnium. I'm not sure anybody knows much about it.
And I realized there was a lot more to say about it than we did the first time.
And in particular,...
...I have a really nice sample,...
...which is relevant,...
...which I'll tell you about in a minute.
No, this is not a sample of Dubnium.
But... Dubnium, like...
...all the elements in this part of the periodic table,...
...can only be made synthetically,...
...by accelerating a light atom...
...into a heavier one, and they fuse together.
In this case, the light atom is Neon,...
...which has atomic number 10, and the heavy atom is Americium,...
...atomic number 95.
10 plus 95 makes 105.
One of the reasons that Dubnium is so important, in my view,...
...is because...
...there was a huge argument...
...between the first experiments,...
...when it was first synthesized, which were in the early 1970s,...
...and the time when it was finally named,...
...which was in the late 1990s.
And really, it was Dubnium and Seaborgium,...
...and the arguments about the naming of these elements,...
...that really sorted out...
...the really amicable way...
...that we now have of considering the discovery...
...of these new super-heavy elements.
The original experiments...
...were done in a place called Dubna,...
...which Brady and I have visited,...
...where the Joint Institute for Nuclear Research is located.
This is a big center for accelerators in Russia.
And you need accelerators to accelerate up the light ions...
...to smash into the heavy target.
And... the difficulty is, you only make these elements...
...one atom at a time.
So it isn't as if you have a large lump of the material to analyze.
The other problem is, they're very short-lived,...
...anything from seconds to a few hours.
So you can't accumulate a lot of atoms. The way you detect them...
...is that... you detect their decay.
They give out gamma rays,...
...and they also form daughter compounds,...
...which themselves decay.
And you can predict with some accuracy...
...what energy of gamma rays you would expect,...
...and then, quite quickly, you get to known radioactive elements,...
...so you can work backwards.
The problem is that,...
...if you want to synthesize...
...really, or as stable an atom as possible,...
...you need to have as many neutrons as possible in your combined atom.
The option for making Dubnium, element 105,...
...with a large excess of neutrons, is not very great.
So they never managed to synthesize any very stable isotopes.
The difficulty came that a rival group...
...in America, in Berkeley,...
...discovered the element at the same time.
And there was a huge argument of priority.
We discovered it first!
There was an interesting meeting...
...between Seaborg...
...and...
...Flyorov, the leader of the Russian team,...
...and they tried to resolve this argument.
But it was unsuccessful,...
...and this led to the idea,...
...after some considerable argument,...
...of forming a committee that would look...
...at the...
...evidence from the different teams,...
...an independent committee, and decide...
...who should take the priority for a particular discovery.
And in the case of Dubnium, it was decided the Berkeley and Dubna teams...
...had discovered it more or less at the same time.
Then why was it named after Dubna?
I think there was then a friendly agreement that it should be named after Dubna,...
...not least because...
...Berkeley already had 3 elements named in its own name,..
...Californium, Americium, and Berkelium.
Plus Seaborgium, Professor.
Seaborgium was named...
...slightly later, but at the same time.
Was there a bit of horse trading going on, do you think?
Like, we'll give you an element if you give us an element?
I suspect. But it was also complicated, because when they finally made the decision,...
...they also named the elements that had been discovered in Darmstadt,...
...Meitnerium, Hassium, and so on.
So they were all named more or less simultaneously
The thing that I think is really remarkable...
...is that, although they have made relatively few atoms of Dubnium,...
...they managed to do a whole series of experiments...
...that can tell you quite a lot about the chemistry.
Dubnium comes immediately underneath Tantalum, in the periodic table.
So you would expect the chemistry of Dubnium to be really quite like Tantalum,...
...but it turns out, when they did experiments,...
that it was perhaps slightly more like Niobium,...
...which is the element immediately above Tantalum in that group.
These are experiments that are just done with a few atoms.
They're looking at the formation of different sorts of compounds,...
...and how these compounds, for example, stick to a piece of glass,...
...or don't stick to a piece of glass,...
...or whether, if you precipitate them, say with a niobium compound,...
...does the radioactivity precipitate, or does it stay in solution?
The reason why these things are interesting...
...is because,...
...as the atoms get bigger and heavier,...
...the relativistic effects caused by the electrons traveling at very high speeds...
...lead to the possibility...
...that the periodic table, the periodic properties, may break down.
So it's really quite important that Dubnium...
...shows the properties of its own group in the periodic table,...
...which shows, at least, that at element 105...
...the periodic properties still behave...
...reasonably as one would expect.
This sample, here, is a piece of granite,...
...sort of red Russian granite,...
...which I picked up on the bank of the river Volga,...
...which flows...
...through...
...the city of Dubna, past the Institute, when Brady and I went there.
So, I got my piece of granite and my Dubna mug,...
...which I use for drinking from.
I think...
...the really important lesson...
...from Dubnium...
...is, that when it was first synthesized,...
...there was huge tension between the different groups around the world...
...that were making these elements.
But now, it's realized...
...that as we go further and further along the periodic table,...
...making heavier and heavier elements,...
...the only way that we're going to succeed as scientists...
...is if everybody works together in a collaborative and friendly way.
So I think you should see Dubnium as...
...the start of this collaboration, which now, as Brady and I have seen, is really warm...
...between the various groups involved
Thank you so much for watching this video,...
...and down in the video description I'll put links...
...from our trip to Dubna, along with other videos about super-heavy elements,...
...and also about... not so heavy elements.
And if you're looking for something different, why not check out my channel, "OBJECTIVITY",...
...where you can watch videos about historic scientific objects, like this,...
...and this,...
...and this as well,...
...and, more recently, this video about the history of driverless cars,...
...and...
...well,...
...I'll let you find out about this thing for yourselves.