Question

The radius of a niobium atom is 131 pm. How many niobium atoms would have to be laid side by side to span a distance of 4.53 mm?
atoms

Answer 1

radius is 131 pm
diameter is 2*131 pm
2*131 pm x (1 mm/10^9) x #atoms = 4.53 mm
Solve for # atoms

Answer 2

1.04x10^-7