Discover the history, structure, and importance of the periodic table of elements ... sulfur, chlorine and argon — have three atomic orbitals where their electrons reside.

Its iconic layout provides scientists with a systematic framework ... scandium and germanium. 5. Did Mendeleev’s periodic table miss anything? When argon was discovered in 1894, it didn’t fit into any ...

But the periodic ... the modern table has a bunch of elements that Mendeleev overlooked (and failed to leave room for), most notably the noble gases (such as helium, neon, argon).

He suspected there were more inert gases filling the corresponding spaces above and below argon in the periodic table, and went looking for them by fractional distillation of liquid air or liquid ...