In "Industrial Alchemy, Part 2: Inorganic Chemical Bestiary" (Grantville Gazette 25), I surveyed the sources and uses of most of the elements of the Periodic Table. However, there were some exceptions:
Lanthanides: 15 elements (these, together with scandium, yttrium, and lutetium, are called "rare earth" elements).
Actinides: 15 radioactive elements.
Non-Metals: The noble gas radon; the radioactive halogen astatine, and the chalcogens selenium, tellurium and polonium.
Alkali (Group 1) Metals: rubidium, cesium and francium.
Alkaline (Group 2) Metals: strontium and radium.
Transition Metals: Group 3 (scandium, yttrium and lutetium); Group 4 (hafnium), Group 7 (technetium, rhenium . . .