Copper has two naturally occurring isotopes, ${ }^{6} \mathrm{Cu}$ (isotopic mass $=62.9296 \mathrm{amu}$ ) and ${ }^{65} \mathrm{Cu}$ (isotopic mass $=64.9278$ amu . If copper has an atomic mass of 63.546 amu, what is the percent abundance of each isotope?
