True the elements are ordered in the atomic number
Answer:
It looks yellow because that is the only (major) color reflected.
Visible spectra is from about 4000-7000 Angstroms (10^-10 m).
Red are longer wavelengths and blue are the shorter wavelengths.
The Sodium doublet (yellow) occurs around 5900 Angstroms.
Im not sure but it might be the last option: it gives reasons to be believed and trusted