Question

1. the atomic mass of rubidium is 85.47 amu. predict which isotope of rubidium is most abundant in nature using this atomic mass. rubidium - 85 rubidium87 rubidium - 37

Explanation:

Step1: Understand atomic mass concept

Atomic mass is the weighted average of isotopes' masses. The isotope closer to the atomic mass is more abundant.

Step2: Compare given atomic mass with isotopes

Rubidium - 85 has a mass of 85 amu. Rubidium - 87 has a mass of 87 amu. The atomic mass of rubidium is 85.47 amu. 85.47 is closer to 85 than to 87.

Answer:

rubidium - 85