Question

What is the definition of relative atomic mass, $A_r$?

• A. $\left(\frac{\text{average mass of naturally occurring atoms of an element}}{{\text{mass of one atom of}}^{12}C}\right)\times 12$
• B. $\left(\frac{\text{average mass of naturally occurring atoms of an element}}{{\text{mass of one atom of}}^{12}C\times 12}\right)$
• C. $\left(\frac{\text{average mass of naturally occurring atoms of an element}}{{\text{mass of one atom of}}^{12}C}\right)$
• D. $\left(\frac{{\text{mass of one atom of}}^{12}C}{\text{average mass of naturally occurring atoms of an element}}\right)$

Answer 1

The correct option is A $\left(\frac{\text{average mass of naturally occurring atoms of an element}}{{\text{mass of one atom of}}^{12}C}\right)\times 12$

It is the ratio of the average mass per atom of an element from a given sample to $\frac{1}{12}$ the mass of a carbon-$12$ atom.

Relative atomic mass, $A_r=\left(\frac{\text{average mass of naturally occurring atoms of an element}}{\text{mass of one atom of}{}^{12}C}\right)\times 12$

Hence, option A is correct.