The modern atomic weight scale is based on

If the molecular mass and atomic mass of sulphur are $256$ and $32$ respectively,its atomicity is:

The unit of atomic mass,$amu$ is replaced by $u$,here $u$ stands for

The atomic weight of $Ne$ is $20.2$. It is a mixture of $Ne^{20}$ and $Ne^{22}$. What is the relative abundance of the heavier isotope (in $\%$)?

Chlorine has two naturally occurring isotopes,${}^{35}Cl$ and ${}^{37}Cl$. If the atomic mass of $Cl$ is $35.45$,the ratio of natural abundance of ${}^{35}Cl$ and ${}^{37}Cl$ is closest to (in $: 1$)

Dulong and Petit's law is valid only for