Question

Assertion:
Atomic number of the element ununtrium is 113.
Reason: According to IUPAC systematic nomenclature, the numerical roots for 1,1 and 3 are un,un and tri respectively
 (A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
 (B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
 (C) Assertion is correct but Reason is incorrect
 (D) Both Assertion and Reason are incorrect

Answer 1

Hint: The IUPAC name is derived straight from the atomic number of the new element by means of the numerical roots prescribed by IUPAC. Hence by identifying the numerical root assigned to each number in the atomic number of element we would be able to verify the given assertion and its reason.

Complete step by step answer:
 - As we know there are around 118 elements in the periodic table. Usually the scientist who discovered gets the opportunity to name the newly discovered element. This name then needs to be consented by IUPAC.
- Initially there were some issues related to nomenclature of elements and in the year 1978 IUPAC made a commission for addressing this issue named CNIC (Commission on Nomenclature of Inorganic Chemistry.
- This commission recommends to write numerical roots of required atomic number from number 0 to 9 and then add the suffix ‘ium’ and the symbol of element consists of initial letters of the numerical roots. This kind of naming system is followed by elements above atomic number 100.
- The given element has the atomic number 113. By the above mentioned method, the numerical root for 1 is un and numerical root for 3 is tri. Thus the element can be named as ununtrium. This confirms both the assertion and reason and as we can see reason is the correct explanation for assertion.
So, the correct answer is “Option A”.

Note: Bear in mind that the final ‘i' of ‘bi’ and ‘tri’ is excluded when it is written before ‘ium’. For example in the case of 113 the by the rule the name would be tri+ium. Here only one ‘i’ is used. Thus the name becomes ununtrium. Also the permanent name for the element 113 is Nihonium.