The Table Grows Bigger: IUPAC announces four new chemical elements of the periodic table of elements

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On December 30th 2015, the International Union of Pure and Applied Chemistry(IUPAC) announced the verification of the discoveries of four new chemical elements for the Periodic Table of Elements. With this remarkable find the 7th row of the periodic table of elements is now complete.

The fourth IUPAC/IUPAP Joint Working Party (JWP) on the priority of claims to the discovery of new elements has reviewed the relevant literature for elements 113, 115, 117, and 118 and has determined that the claims for discovery of these elements have been fulfilled, in accordance with the criteria for the discovery of elements of the IUPAP/IUPAC Transfermium Working Group (TWG) 1991 discovery criteria. These elements complete the 7th row of the periodic table of the elements, and the discoverers from Japan, Russia and the USA will now be invited to suggest permanent names and symbols.

The properties and the temporary names and Symbols of the new elements are as follows,

 

Element 113

Atomic Number – 113

Temporary Name – ununtrium

Temporary Symbol – Uut

Research Team – The RIKEN collaboration team, Japan

 

Element 115

Atomic Number – 115

Temporary Name – ununpentium

Temporary Symbol – Uup

Research Team – Joint Institute for Nuclear Research in Dubna, Russia; Lawrence Livermore National Laboratory, California, USA; and Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA

 

Element 117

Atomic Number – 117

Temporary Name – ununseptium

Temporary Symbol – Uus

Research Team – Joint Institute for Nuclear Research in Dubna, Russia; Lawrence Livermore National Laboratory, California, USA; and Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA

 

Element 118

Atomic Number – 118

Temporary Name – ununoctium

Temporary Symbol – Uuo

Research Team – Joint Institute for Nuclear Research in Dubna, Russia; Lawrence Livermore National Laboratory, California, USA; and Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA

new elements
With the discovery of these four new elements the 7th row of Periodic Table is now complete – Image – IUPAC website

“A particular difficulty in establishing these new elements is that they decay into hitherto unknown isotopes of slightly lighter elements that also need to be unequivocally identified” commented JWP chair Professor Paul J. Karol, “but in the future we hope to improve methods that can directly measure the atomic number, Z“.

“The chemistry community is eager to see its most cherished table finally being completed down to the seventh row. IUPAC has now initiated the process of formalizing names and symbols for these elements temporarily named as ununtrium, (Uut or element 113), ununpentium (Uup, element 115), ununseptium (Uus, element 117), and ununoctium  (Uuo, element 118)” said Professor Jan Reedijk, President of the Inorganic Chemistry Division of IUPAC.

The proposed names and symbols will be checked by the Inorganic Chemistry Division of IUPAC for consistency, translatability into other languages, possible prior historic use for other cases, etc. New elements can be named after a mythological concept, a mineral, a place or country, a property or a scientist (see: W.H. Koppenol, PAC 74 (2002) 787-791). After Divisional acceptance, the names and two-letter symbols will be presented for public review for five months, before the highest body of IUPAC, the Council, will make a final decision on the names of these new chemical elements and their two-letter symbols and their introduction into the Periodic Table of the Elements.

“As the global organization that provides objective scientific expertise and develops the essential tools for the application and communication of chemical knowledge for the benefit of humankind, the International Union of Pure and Applied Chemistry is pleased and honored to make this announcement concerning elements 113, 115, 117, and 118 and the completion of the seventh row of the periodic table of the elements,” said IUPAC President Dr. Mark C. Cesa, adding that, “we are excited about these new elements, and we thank the dedicated scientists who discovered them for their painstaking work, as well the members of the IUPAC/IUPAP Joint Working Party for completing their essential and critically important task.”

The superheavy elements

These newly discovered elements belongs to the element group called superheavy elements. Elements heavier than Rutherfordium (element 104) are referred to as superheavy. They are not found in nature, because they undergo radioactive decay to lighter elements.

Those superheavy nuclei that have been created artificially have decay lifetimes between nanoseconds and minutes. But longer-lived (more neutron-rich) superheavy nuclei are expected to be situated at the centre of the so-called “island of stability”, a place where neutron-rich nuclei with extremely long half-lives should exist.

Currently, the isotopes of new elements that have been discovered are on the “shore” of this island, since we cannot yet reach the centre.

How hard is it to discover these Superheavy Elements?

Atoms of superheavy elements are made by nuclear fusion. But it’s not easy as it seems.

The problem in the fusion of heavy nuclei is the large numbers of protons in both nuclei. This creates an intense repulsive electric field. A heavy-ion accelerator must be used to overcome this repulsion, by colliding the two nuclei and allowing the nuclear surfaces to touch.

This is not sufficient, as the two touching spheroidal nuclei must change their shape to form a compact single droplet of nuclear matter – the superheavy nucleus.

It turns out that this only happens in a few “lucky” collisions, as few as one in a million.

And also the life time of the created superheavy atom is very short as it is very likely to decay almost immediately by fission.

The process of superheavy element creation and identification thus requires large-scale accelerator facilities, sophisticated magnetic separators, efficient detectors and time.

Finding the three atoms of element 113 in Japan took 10 years, and that was after the experimental equipment had been developed.

Why these new Discoveries are important to the mankind in general ?

The payback from the discovery of these new elements comes in improving models of the atomic nucleus (with applications in nuclear medicine and in element formation in the universe) and testing our understanding of atomic relativistic effects (of increasing importance in the chemical properties of the heavy elements). It also helps in improving our understanding of complex and irreversible interactions of quantum systems in general.