<span>The answer is 5.7 x 10–4 M.
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Which of these describes atomic radii as one moves from top to bottom within a group? the atomic radius decreases from top to bottom within a group. the atomic radius does not vary in any predictable way within a group. the atomic radius is the same within a group.
correct answer
the atomic radius increases from top to bottom within a group?
You must see the mass of Gallium in the periodic table. The mass present there is calculated by a weighted average of the mass of the isotopes, where the weights are the abundances of each isotope. Let X the isotopic abundance of Ga⁷¹. Since there are only Ga⁶⁹ and Ga⁷¹, the isotopic abundance of Ga⁶⁹ is 1-X. Then:

I don't know the options, but probably 40% is the closest to 36.15%.