Question

Element X has two naturally occurring isotopes, 35X and 36X . 35X has a percent natural abundance of 30%, while 36X has a percent natural abundance of 70%. What is the average atomic mass of element X

Answer 1

= 35.7 amu

Step-by-step explanation:

Isotopic fractional Wt Avg mass

mass (amu) abundance (= % / 100) = Isotopic mass X (= % / 100)

X-35 35 0.30 10.5 amu

X-36 36 0.70 25.2 amu

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Average Atomic Mass of Element X = ∑ Wt. Avg. Masses = 35.7 amu