PaRaNoIAcS and CHAmBErLaInS in the Nov 1974 Word Ways. Of these, arsenic, tin, copper and carbon do not use their own abbreviations.
Elemental words are often expressible in more than one way.
Among three-letter words, SIN, SiN, SIn and TIN, TIn, TiN have three representations. The shortest word expressible in four ways is COHO, COHo, CoHO, CoHo, and the shortest expressible in five is SINeS, SiNeS, SInEs, SINEs, SiNEs. A difficult but solvable challenge is to find elemental words incorporating all 103 different elements. WHeN HEr LaDy IS NeArBY, AgNUS STaYS, I NoTe. No AgNUS HeRe.