Question

Rubidium has two naturally occurring isotopes: 85Rb, with mass 84.9118 amu and natural abundance 72.15%; and 87Rb, with mass 86.9092 amu and natural abundance 27.85%. Calculate the atomic mass of rubidium. View Available Hint(s) Rubidium has two naturally occurring isotopes: 85Rb, with mass 84.9118 amu and natural abundance 72.15%; and 87Rb, with mass 86.9092 amu and natural abundance 27.85%. Calculate the atomic mass of rubidium. 86.3529 amu 84.9118 amu 85.9105 amu 85.4681 amu

Answer 1

85.4681 amu

Step-by-step explanation:

We shall take weighted average of isotopes

Atomic mass of Rubidium

`=(.7215* 84.9118 + .2785* 86.9092)/(.7215+.2785 )`

= 61.26386 + 24.2042122

= 85.4681 amu .