Relative atomic mass (Edexcel GCSE Chemistry): Quizzes

$\frac{1}{12}$ the mass of a carbon-12 atom

Weighted average of all isotopes

$Ar$ considers all isotopes; mass number is for one isotope

$35.5$

Different isotopes contribute to $Ar$

On the periodic table

Abundance of each isotope

$\frac{\text{Mass}}{Ar \text{ or } Mr}$

Relative formula mass ($Mr$)

$10.8$