## Chemistry: The Central Science (13th Edition)

The wavelength range of the visible part of the electromagnetic spectrum is from $400nm$ to $750nm$. Now we compare the characteristic wavelengths of the elements with the wavelength range of the visible part to see which wavelength fits in the range. There are 4 elements whose characteristic wavelengths fit in the range of the visible part: Ba $(455.4nm)$, Ca $(422.7nm)$, K $(404.7nm)$ and Na $(589.6nm)$ These are the elements which would emit radiation in the visible part of the spectrum.