Answer:
6960000 Nickel atoms
Step-by-step explanation:
radius = 125 pm = 125 x 10^-12 m
diameter of each atom = 125 pm x 2 = 250 pm = 250 x 10^-12 m
span of distance to be achieved = 1.74 mm = 1.74 x 10^-3 m
number of nickel atoms = (1.74 x 10^-3 m)/(250 x 10^-12 m) = 6960000 Nickel atoms