Why is it important to measure the mass of an atom?

Tin has ten stable isotopes. the heaviest, 124sn, makes up 5.80% of naturally occuring tin atoms. how many atoms of 124sn are present in 82.0 g of naturally occurring tin? what is the total mass of the 124sn atoms in this sample?

Light waves travel than sound waves.

Rank substituents in order of their priority when assigning the e or z label to an alkene. i, ch2i , h, ch2ch2cl, f