The atomic mass of the element would simply be equal to
the sum of the weighted average of each isotope, that is:
atomic mass = 59.015 amu * 0.717 + 62.011 amu * (1 – 0.717)
<span>atomic mass = 59.863 amu</span>
Very simply, you get twice as much Hydrogen as Oxygen, because the chemical formula is H2O, meaning two hydrogen atoms bonded to one oxygen atom.
