And they are…
Nihonium, named after Japan (Nippon is a Japanese word for Japan), with an atomic number of 113. Its symbol is Nh.
Moscovium (Mc), element 115, named after the Russian capital city.
Tennessine (Ts), 117, named after — you guessed it — the state of Tennessee. ("Tennessine is in recognition of the contribution of the Tennessee region, including Oak Ridge National Laboratory, Vanderbilt University, and the University of Tennessee at Knoxville, to superheavy element research," the IUPAC states.)
And finally, 118 is oganesson (Og), which bears the name of Russian physicist Yuri Oganessian, who led several elemental discoveries. Nature reports this is only the second time an element has been named for a living scientist.
(An online petition called for one of these heavy metal elements to be named for the late Motörhead frontman "Lemmy" Kilmister. The request was ignored.)
The proposed names will be confirmed after a five-month period of public review. (Considering how uncontroversial these names are, it seems likely the names will stick).
And for the scientist who made the discoveries, this is a huge honor. "To scientists, this [naming an element] is of greater value than an Olympic gold medal," Ryoji Noyori, a Nobel Prize winner, explained to the Guardian in January.
There are some constraints to naming, however. The IUPAC rules stipulate new elements must be named after either
- "A mythological concept or character (including an astronomical object)"
- "A mineral, or similar substance"
- "A place or geographical region"
- "A property of the element"
- "A scientist"
A quick refresher on the periodic table
This is the periodic table of the elements. It describes the weight and chemical properties of all the known elements in the universe.
It follows these rules (generally, although there are many exceptions).
Going from left to right across the periodic table, elements are arranged by:
- Lighter to heavier
- More metallic to less metallic
- More positively charged to more negatively charged to inert (neither positively or negatively charged)
The genius of the periodic table is that its inventor, Dmitri Mendeleev, discovered that as elements grow heavier, this pattern repeats itself. Each time the pattern repeats, a new row forms.
The result is a table that allows a person to both easily scan the weight of elements and guess at how they will react with other elements on the table. So we know that chemically, sodium (symbol Na) acts a lot like potassium (symbol K), even though potassium is nearly double the weight of sodium. And so on.
These four new elements don't exist naturally
Every element is given an atomic number, which corresponds to the number of protons in its nucleus. Hydrogen, the lightest element, has an atomic number of 1, and its nucleus contains one proton. Element No. 2 — helium — has two.
These new elements have 113, 115, 117, and 118 protons respectively. Atoms with that many protons are too unstable to exist in nature. That's because protons naturally repel one another. In smaller atoms, the strong nuclear force — the powerful energy that is unleashed in a nuclear explosion — keeps the protons bonded. But in larger atoms it loses its grip, and the atoms decay into more stable elements with fewer protons.
(Uranium, with 92 protons, is the heaviest element to exist naturally.)
How to create new, heavier elements: smash together lighter ones
Elements with very high atomic numbers have to be created by smashing together two smaller atoms in the hope that some of their protons stick together.
To create tennessine with a atomic number of 117, Scientific American explains, "the researchers smashed calcium nuclei (with 20 protons apiece) into a target of berkelium (97 protons per atom)." But this is much harder than it sounds. Berkelium (named after Berkeley, California) is extraordinarily rare; it took the team more than two years to stockpile 13 milligrams of it for the purpose of the experiment.
Once created, tennessine almost instantaneously decays and disappears. It has a half-life (the amount of time it takes for half of a given amount of the element to decay) of fifty-thousandths of a second. Nihonium — created by bombarding bismuth with zinc ions — is also fleeting: It decays in less than a thousandth of a second, its Japanese discoverers reported.
What's the point of discovering new elements?
So why prove the existence of these barely there elements with no apparent practical value? One, because we can. It's important to prove scientific theories with observational data. It strengthens further predictions we can make from the periodic table.
Two, because we may, one day, create some very heavy, very useful new elements.
Quantum theory posits that it may be possible to create extremely heavy elements — with more than 120 protons — that are also very stable (meaning they'd resist decay). These elements would exist in an "island of stability" at the end of the periodic table, and no one knows what properties they might have.