Magnesium has three isotopes. 78.99% magnesium 24 with a mass of 23.9850 amu, 10.00% magnesium 25 with a mass of 24.9858 amu, and the rest magnesium 25 with a mass of 25.9826 amu. What is the atomic mass of magnesium?
If not told otherwise, the mass of the isotope is the mass number in amu
Is not a whole number because it is an average.
are the decimal numbers on the periodic table.