Electron Color

Source - https://xkcd.com/2734/ 

See, it's funny because the teacher is scientifically correct in the second panel...but the teacher still knows what color electrons are.

From wikipedia, the radius of an electron is somewhere between 10^-18 and 10^-22 meters.  The wavelengths of visible light fall in the range of 3 x 10^-7 and 7 x 10^-7 meters. This means the an electron's radius is something like a trillion times smaller than the wavelength of visible light.

But most diagrams of the atom show protons and neutrons to be red and either blue or green. The color of the electrons in the diagrams I found at the top of Google's image search were less consistent - grey, yellow, dark blue, green, or even multicolored.

Clearly in Miss Lenhart's world, though, electrons are yellow.