Chemistry · Classification of Elements and Periodicity in Properties

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The atomic number of an element is a more fundamental property than its atomic mass. Reason (R): Moseley showed that a plot of \( \sqrt{\nu} \) of characteristic X-rays emitted from an element against atomic number gives a straight line, whereas atomic mass does not give such a simple linear correlation. In the light of the above statements, choose the correct answer from the options given below:

1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.