An element has three naturally occurring isotopes. Use the information below to calculate the weighted average atomic mass of the element, showing both the setup and the final answer for the calculation.

Isotope

Atomic Mass

Percent Abundance

I

39.96 u

99.59%

II

37.96 u

0.065%

III

35.97 u

0.336%

Question

An element has three naturally occurring isotopes. Use the information below to calculate the weighted average atomic mass of the element, showing both the setup and the final answer for the calculation.


Isotope

Atomic Mass

Percent Abundance

I

39.96 u

99.59%

II

37.96 u

0.065%

III

35.97 u

0.336%

syedmohammed98 · Answer

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anonymous · Answer

Thank you! I put 
In order to find the weighted average atomic mass I first altered the percentage to a decimal. I then multiplied by the isotope for all three. I then added them all together resulting in my final answer of 39.942
as my answer but I was simply not sure if I was right.

syedmohammed98 · Answer

Your'e Welcome :)
You can also solve the whole thing without altering the percentages ..once you get the answer, you can then change it according to the need of the question.