Determine the relative weighted average atomic mass of the element neon, given the following information,

Isotope

Relative Mass (u)

% Abundance

20Ne

19.992440

90.48

21Ne

20.993846

0.27

22Ne

21.991385

9.25

Answer:

To calculate the relative, weighted average atomic mass we use the mathematical equation,

weighted average = (atomic mass ­ fractional abundance)1 + (atomic mass ­ fractional abundance)2 + (atomic mass ­ fractional abundance)2

substituting,

weighted average = (19.992440 ­ 0.9048)1 + (20.993846 ­ 0.0027)2 + (21.991385 ­ 0.0925)2 = 20.18 u