The periodic table is emblazoned on walls worldwide.
We learn about it.
We memorize it.
We think of it as set in stone.
But … it’s not.
This iconic table defines the elements
that make up all earthly substances
and guides all of chemistry.
And it’s evolved more than you might think.
In 2016, it got four new elements.
And scientists are currently seeking the next additions.
But how do elements earn a coveted spot on the table?
[music]
Announcer: Recorded in front of a live studio audience
Getting a big break doesn’t happen overnight.
It takes hard work and proof.
The laws of chemistry and physics predict the existence
of never-before-seen elements waiting to be discovered.
So it’s up to scientists to decide
which elements deserve a shot.
Each element on the periodic table is made up
of a different number of protons.
So scientists are looking for two known elements
that they can smash together to create a new element
with a different number of protons
than we’ve ever seen before.
To make element 118, called oganesson, scientists
used calcium, with 20 protons, and californium, with 98.
Here’s how it works.
A beam of ions of one element is shot
at atoms of the other element.
With luck, the two fuse, forming the new element.
But often they don’t.
And even when they do,
the new elements are often unstable.
They can decay in mere milliseconds.
To make just six atoms of tennessine,
scientists battered berkelium with calcium for 150 days.
It wasn’t always this way.
The 63 elements Dmitrii Mendeleev put in
the first periodic table were already big names.
He even left space for undiscovered elements.
Most of those elements and others soon showed up
in nature, isolated from minerals, for example.
But eventually scientists had to turn to artificial means
to keep filling out the periodic table
and keep pushing the limits of matter.
Nothing beyond uranium exists in abundance in nature,
making today’s brute-force approach necessary.
Fleeting lifetimes also make some of these elements
extremely hard to verify.
Enter, the judges.
The International Union of Pure and Applied Chemistry
and the International Union of Pure and Applied Physics
convene a group to review new element claims.
How do they decide?
Telltale evidence could come from
the element’s decay chain.
The timing and associated energies
can help seal the verdict.
Sometimes it’s hard to be sure, though.
A team in Japan first glimpsed element 113 in 2004,
but the decay pattern wasn’t conclusive enough.
It took nine years firing 135 quintillion zinc ions
at bismuth for 113 to earn its spot.
The modern system is not without controversy.
Initial claims for elements 116 and 118 went bust
because one researcher appeared to have
faked the results.
[record scratch]
Once the data are solid,
the reviewers decide who gets credit,
and the element makes its debut.
And the discoverers get to name
and pick symbols for their elements,
though there are a lot of rules.
But adhering to those rules is a small price
to pay for fame.
If an element makes the cut,
generations will remember its name.
And that’s way better than a record deal.
[cheering]
[music]
