Question

Calculate the average atomic mass for the following element given information about the relevant isotopes: (Isotope 1) Mass = 20 amu; Isotopic abundance = 90.92% (Isotope 2) Mass = 21 amu; Isotopic abundance = 0.257% (Isotope 3) Mass = 22 amu; Isotopic abundance = 8.82%

Answer 1

Answer:

The average atomic mass of given element is 20.18 amu.

Explanation:

Given data:

Abundance of 1st isotope mass 20 amu = 90.92%

Abundance of 2nd isotope mass 21 amu = 0.257%

Abundance of 3rd isotope mass 22 amu = 8.82%

Average atomic mass = ?

Solution:

Average atomic mass  = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass)  / 100

Average atomic mass  = (90.92×20)+(0.257×21)+(8.82×22) /100

Average atomic mass =  1818.4 + 5.397 +194.04 / 100

Average atomic mass  = 2017.819 / 100

Average atomic mass = 20.18 amu.

The average atomic mass of given element is 20.18 amu.