Ahypothetical element contains three isotopes of mass 16.0 amu, 17.0 amu, and 18.0 amu with relative abundances of 20.0%, 50.0% & 30.0%, respectively. the average atomic mass is:

- 17.1 is the average atomic mass.

Solution:- To calculate the average atomic mass we convert the given percent abundances to the decimals and multiply by their restive isotopic masses and take the sum of all these.

Average atomic mass = 16.0(0.20)+17.0(0.50)+18.0(0.30)

average atomic mass = 3.20+8.50+5.40

average atomic mass = 17.1

Therefore, the average atomic mass is 17.1.