Answer:
Average atomic mass of Rb = 85.6 amu.
Explanation:
Abundance of Rb⁸⁵ = 72.2%
Abundance of Rb⁸⁷ = 27.8%
Average atomic mass = ?
Solution:
Average atomic mass of Rb= (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass of Rb = (85×72.2)+(87×27.8) /100
Average atomic mass of Rb = 6137 + 2418.6 / 100
Average atomic mass of Rb = 8555.6 / 100
Average atomic mass of Rb = 85.6 amu.
