The seventh row of the chemical periodic table has now been completed with the recent discovery of four new elements by a team of scientists from Russia, US and Japan.

The International Union of Pure and Applied Chemistry (IUPAC) on December 30 verified that elements 113, 115, 117 and 118 discovered by the international team of scientists met the criteria for the discovery of elements of the IUPAP/IUPAC Transfermium Working Group (TWG) 1991.

With this new development, incidentally the first since 2011 when elements 114 and 116 were added, periodic tables in textbooks around the world will have to be modified again.

“The chemistry community is eager to see its most cherished table finally being completed down to the seventh row,” Professor Jan Reedijk, president of the Inorganic Chemistry Division of IUPAC, said in a statement.

These artificial elements, which were discovered by slamming lighter ­nuclei into each other and tracking the decay of the resultant radioactive super-heavy elements, are yet to be named.

The teams belonged to Russia’s Joint Institute for Nuclear Research in Dubna, the Lawrence Livermore National Laboratory in California and the Riken Institute in Japan.

 The elements have been named ununtrium (113), ununpentium (115), ununseptium (117) and ununoctium (118) respectively for the time being.

 All these elements are highly unstable and cannot exist in nature for long before breaking down into smaller elements. But Ryoji Noyori, a Nobel laureate in chemistry told the Guardian, “To scientists, this is of greater value than an Olympic gold medal.”