1. Determine the element's average atomic mass number using the periodic table of the elements. This will be a number with several decimal places behind it. This value is the average
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The atomic mass of an element is the weighted average of the masses of its isotopes. You know that: Antimony121 has a mass of 120.9038 u, x% abundance Antimony123 has a mass of
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To find the average atomic mass, we multiply the mass of the isotope by the percent abundance in decimals (and we add isotopes into our equation depending on how many there are) Also
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Subtract the larger number from the smaller and divide and multiply. Here is a formula. Divide A/B=C C x 100=D%D%100%E the percentage.
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