8.10 x 10^-21 microliters
This requires you to know what the prefixes are and what the volume of a liter is. The volume of a liter is 1000 cubic centimeters (cm^3). micro is one millionth (10^-6). So a microliter is one millionth of a liter, or 0.001 cubic centimeters (1 x 10^-3 cm^3).
So divide the volume of a nickel atom in cm^3 by the volume of a microliter to get the answer.
8.10x10^-24 / 1 x 10^-3 = 8.10x10^-21
