The average human hair has a diameter of 100,000 nm. We can see individual hairs because hair has a diameter greater than the wavelengths of the visible spectrum. (ranges from about 700 to 400 nm). An individual iron atom has a diameter of about 0.3 nm. Can we ever "see" an individual iron atom with visible light?
a) Yes, because the individual iron atom has a diameter much larger than visible light wavelengths.
b) No, because the individual iron atom has a diameter much smaller than the visible light wavelengths.
c) Can't tell because there is no correlation between size of an object and light reflecting off of it.