The diameter of a neutral neon atom is about 1.4 ✕ 10^2 pm. Suppose that we could line up neon atoms side by side in contact with one another. Approximately how many neon atoms would it take to make the distance from end to end 1 cm?

Question

I did 1.4 x 10^2 pm x (1 m/10^9 pm) x (100 cm/1 m) = 1.4 x 10^-05 but this answer is not correct

Answer 1

What you did, and you needed to that, is convert 1.4E2 pm to cm.
Then (1.4E-5 cm/atom) x # atoms = 1 cm.
Solve for # atoms in the 1 cm.