Question

Copper occurs in nature in the form of two isotopes, Cu-63 and Cu-65. Its correctly recorded atomic mass (weighted average) is 63.5 amu. Without doing the math, explain why it is safe to say that Cu-63 is more abundant than Cu-65.

Answer 1

63.5 is closer to 63 than 65 so you know when they find the average mass there are more Cu-63 isotopes