Why can't we see an atom with the naked eye?

An atom is a miniscule particle that measures approximately 0.1 to 0.5 nanometers. 1 nanometer = 1×10⁻⁹ meters or 1/1000000000 meters. It is not possible for the naked eye to see particles that are so small. The only way the human eye can see an atom is under a microscope.