What is the atomic mass of a hypothetical element that consists of the following

ID: 704272 • Letter: W

Question

What is the atomic mass of a hypothetical element that consists of the following isotopes in the indicated natural abundances?

Isotope Isotopic mass
(amu) Relative abundance
(%)
1 85.9 12.2
2 86.9 15.0
3 90.9 72.8

Express your answer to three significant figures and include the appropriate units.

What is the atomic mass of the element that consists of the following isotopes in the indicated natural abundances?

Express your answer to three significant figures and include the appropriate units.

Isotope Isotopic mass
(amu) Relative abundance
(%) 1 57.93 67.76 2 59.93 26.16 3 60.93 1.25 4 61.93 3.66 5 63.93 1.16

Ans :

The atomic mass of an element is the average of sum of the masses of its isotopes , each multiplied by its relative abundance.

So here :

M = [ (85.9 x 12.2) + (86.9 x 15.0) + (90.9 x 72.8) ] / 100

= 89.7 amu

M = [ (57.93 x 67.76) + (59.93 x 26.16) + (60.93 x 1.25) + (61.93 x 3.66) + (63.93 x 1.16) ] / 100

= 58.7 amu

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.