The atomic mass of element A is 63.6 atomic mass units. The only naturally occurring isotopes of element A are A-63 and A-65. What is the percent abundance in a naturally occurring sample of element A closest to?

1 Answer
Dec 12, 2016

The most abundant isotope is #""^63A#.

Explanation:

The average isotopic mass is the weighted average of the mass of the individual isotopes. Because the quoted average, #63.6# #"amu"#, is closer to #""^63A# than #""^65A#, the #""^63A# isotope is the more abundant. Can you tell us which metal this element is?