Not so long ago, the nightscapes of many American cities were bright with brilliant electric signs and the rainbow hues of glowing neon. Actually, neon (Ne) is used for red and orange. The other noble gases on the Periodic Table of Elements, argon (Ar), helium (He), krypton (Kr), and xenon (Xe), are used for other colors along with phosphors and a bit of mercury (Hg). The sixth member of the nobility is radon (Rn), but it’s radioactive and not to be messed with.
