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  • I'm gonna ask you to go to your bookshelf, and take out your old chemistry textbook.

  • If you don't have one of those somewhere, in your life, I feel sorry for you, because

  • everyone should have at least one Chemistry textbook in their life.

  • But assuming you do, open it up and take a look at the periodic table of elements. It's

  • probably on the inside cover.

  • See that?

  • It is no longer accurate.

  • Totally outdated.

  • Now, you have to go buy yourself a new $700 textbook because the periodic table of elements

  • has just changedagain!

  • Last Wednesday, the final four elements on the seventh row of the periodic tablethe

  • ones with the atomic numbers 113, 115, 117, and 118 – were finally given names.

  • Depending on how old your textbook is, those elements either don't have names, or aren't

  • there at all.

  • Buthold upthe periodic table isn't finished yet!

  • It took years to create these latest elements, and now scientists have their sights set on

  • creating more new super-heavy elements in row 8, with atomic numbers 119 and above.

  • Butno one knows how they're gonna manage to do that.

  • To create the four latest elements, scientists had to smash lighter elements together using

  • huge instruments like particle accelerators.

  • And it can take millions of collisions to create just a single atom of a new element.

  • But the thing is, once an atomic nucleus reaches a certain sizelike anything bigger than

  • uranium, with an atomic number of 92 – the atom becomes unstable.

  • That's because the forces that are holding all the neutrons and protons of the nucleus

  • together aren't strong enough to hold them together over longer distances, when there

  • are more particles.

  • So bigger elements are also more unstable, and they tend to decay, or break apart into

  • other atoms with smaller nuclei, in just fractions of a second.

  • So, in order to prove that they've created one of these new, super-heavy elements, scientists

  • have to collect evidence of this decay.

  • One way they do this is to record the radiation that's released as a new element breaks down.

  • This radiation is often released as a series of alpha particles, which are essentially

  • helium nuclei, with 2 protons and 2 neutrons.

  • Since each alpha particle has an atomic mass of 4, scientists can basically measure how

  • many particles were emitted, and work backward to figure out how big the atom was that released all of them.

  • Plus, the bigger the nucleus, the more energy there is in each of the emitted alpha particles

  • which the researchers can also measure.

  • After all that, once there's enough evidence that a new element has been created, the element

  • gets the stamp of approval of the International Union of Pure and Applied Chemistrythe

  • official entity that gets to decide these things.

  • Then the IUPAC lets the scientists who made the discovery pick a name.

  • And the rules say that they can use any word from a myth, a mineral, a place, a property

  • of the element, or a scientist.

  • Kinda like Mad-Libs for chemists.

  • So let's start with the first newly named element: element 113, now known as Nihonium.

  • It's named after the Japanese word Nihon, which meansLand of the Rising Sun,”

  • a reference to the country of Japan.

  • This discovery was the first to be made by an Asian country, and is attributed to the

  • Japanese research center that used a particle accelerator to bombard a bunch of bismuth

  • with atomic number 83 – with a beam of zinc ionswith atomic number 30.

  • Next up are elements 115 and 117, which were made in collaboration between labs in Dubna,

  • Russia, and California and Tennessee in the U.S.

  • Element 115 is now called Moscovium, to honor the city of Moscow and the team of Russian

  • scientists that first created the element in 2003.

  • The team smashed atoms of calciumwith atomic number 20 – into a sheet of americium

  • with atomic number 95 – and other labs around the world repeated their experiments

  • over the next decade to confirm its existence.

  • As for element 117, its proposed name is Tennessine for all the labs in Tennessee that worked

  • on this and other super-heavy elements.

  • Tennessine is the most recently discovered element, first created in 2010 by shooting

  • calcium at another synthetic elementberkelium, with atomic number 97.

  • And the last new element, 118, will be named Oganessonto honor Yuri Oganessian, the

  • nuclear physicist who leads the Russian research team that helped discover several super-heavy

  • elements, including this one.

  • Element 118 was first synthesized around 2002, and again around 2005, by bombarding californium

  • with atomic number 98 – with calcium.

  • So, what's next?

  • Well, element 119 obviously.

  • But, obviously, no one has succeeded in creating an atom that big yet!

  • Some researchers say that creating elements past the seventh row of the periodic table

  • is gonna be tricky, because we're reaching the limit of what our particle accelerators

  • and measurement devices can do.

  • We're going to have to learn how to stabilize, manipulate, and collide bigger atoms before

  • we can figure out how big the periodic table can get.

  • So, probably don't toss that old chemistry textbook.

  • It's just going to need to be updated someday... probably

  • If we keep working hard... being cool science people.

  • We humans have a lot more to learn.

  • Thanks for watching this episode of SciShow News, and thanks especially to all of our

  • patrons on Patreon who make this show possible. If you want to help us keep making videos

  • like this, just go to patreon.com/scishow­. And if you just want to keep getting smarter

  • with us you can go to youtube.com/scishow and subscribe!

I'm gonna ask you to go to your bookshelf, and take out your old chemistry textbook.

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B1 中級 美國腔

认识 4 个最新元素(Meet the 4 Newest Elements!)

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    joey joey 發佈於 2021 年 07 月 02 日
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