Question

Assertion :Relative atomic mass of chlorine is 35.5. Reason: Chlorine gas is a diatomic element.

Choose the correct option:

• 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. Assertion is incorrect but Reason is correct

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Atomic mass is the ratio of the mass of the average of all isotopes of an element. Chlorine exists in the form of 2 isotopes, ${}_{17}^{35}Cl$ and ${}_{17}^{37}Cl$. Approximately 1 atom out of every four is of ${}_{17}^{37}Cl$

hence the relative atomic mass = 35.5

Chlorine exists in nature as $\left(C{l}_2\right)$ Thus, 2 atoms of chlorine shared one electron each from the outermost shell of their orbits and form $\left(C{l}_2\right)$ molecule. Thus, atomicity of chlorine is 2.