Calculating Mr (Relative Formula Mass/Relative Molecular Mass):
To calculate the Mr of a compound, you add the mass number of each of the elements
e.g.
NaCl = 23 + 35 = 58
or
MgBr2 = 24 + 80 + 80 = 184
To calculate the Mr of a compound, you add the mass number of each of the elements
e.g.
NaCl = 23 + 35 = 58
or
MgBr2 = 24 + 80 + 80 = 184