Answer
Atomic mass of rubidium is 85.76 amu.
Work Step by Step
The atomic mass is a sum function of relative abundances of isotopes.
As we can see on the graph, the abundance of Ru-85 is 100%, and by its name, the value of its mass is approximately 85 amu.
If we repeat the process for Ru-87, we get an abundance of about 38% and a mass of 87 amu.
- Calculate the atomic mass of rubidium:
atomic mass = 85 x (1 - .38) + (87 x 0.38) = 85.76 amu
