Explanatory notes
… The radioactive alkali metal francium is excluded ( heading 28.44 ). (B) ALKALINE‑EARTH METALS The three alkaline‑earth … does not include radium, a radioactive element ( heading 28.44 ), magnesium ( heading 81.04 ), or beryllium ( heading … 61), which is radioactive, is classified in heading 28.44 . The rare‑earth metals are generally greyish or …