How does the size of a nanoparticle compare with the size of an atom?

A nanoparticle is larger than an atom. A nanoparticle is usually made from a few hundred atoms. These  particles range from 1 nanometers to 100 nanometers. On the other hand an atom ranges from 0.1 nanometers to 105 nanometers. Using the sizes above, one can clearly see and understand that an atom is smaller. 

Determine the  wavelength of light emitted when an electron  in an li2+ ion  makes a transition from an orbital with n  =  6 to an orbital with n  = 5.