Question

Assume that the atomic diameter of an atom of element X is 2A and that 1.0 x 10(16th) atoms are arranged in a simple 2D square array. What is the length of each side in cm?

Answer 1

I would draw a 2D square. Each side is 1E8 atoms. If each atom is 2E-8 cm (that's 2 Angstroms each), then
1E8 atom x (2E-8 cm/atom) = ?

Answer 2

Is it 2E-11?

Answer 3

I don't think so. How do you add 8 and -8 and get -11.