Relative Atomic mass: Given by the symbol Ar
- Calculated from the mass number and relative abundances of all the isotopes of a particular element
Use information from the table to calculate the relative atomic mass of this sample of rubidium. Give your answer to one decimal place
( 72 x 85 ) + ( 28 x 87 )
____________________________ = 85.6
Relative Atomic Mass = 85.6
Relative formula mass: Given by the symbol Mr, is the total mass of the molecule.
- To calculate the Mr of a substance, you have to add up the Relative Atomic Masses of all the atoms present in the formula