Question

Recently (in Aug 2003) two new elements have been discovered with atomic numbers:
A) $113,114$
B) $114,115$
C) $115,116$
D) $113,115$

Answer 1

As we know that recently two superheavy elements have been fleetingly created in a Russian laboratory and each has many more protons and neutrons in their nuclei than any naturally occurring elements found on Earth.

Complete answer
Recently two new superheavy elements were discovered in Russian laboratory and nuclei of these two elements are crammed with $113$ and $115$ protons. These new elements are created using a machine called particle accelerator in Dubna, Russia by a researcher’s team from Joint Institute for Nuclear Research in Dubna and the Lawrence Livermore National Laboratory in California, US.

So, these elements are numbered as $113$ and $115$ and were named as Nihonium and Moscovium.
Both of them are highly unstable and more radioactive super heavy metals. Heavy metals are those metals that have an atomic number larger than $92$ and super heavy elements are those which have an atomic number larger than $112$. Super heavy metals do not occur in nature but are created in closed and safe environments like laboratories.

Also remember that because of the high number of protons these elements immediately decompose into other elements and thus have a short life of fraction of seconds. Nihonium has a half-life of almost ten seconds. Therefore from the above explanation the recently found elements are $113$ and $115$.

Hence, the correct answer is option (D).

Note: Nihonium and Moscovium immediately decompose into other elements because their protons in nuclei are high in number and as we know protons are positively charged so they repel each other and thus become more unstable.