Crossword clues for protoactinium
Wiktionary
n. (alternative form of protactinium English) (qualifier: dated)
WordNet
n. a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead [syn: protactinium, Pa, atomic number 91]
Usage examples of "protoactinium".
And number ninety-nine is naturally radioactive, breaking down to protoactinium by a double emission of alpha particles.
The intermediate elements referred to in this radioactive decay chain are lead (symbol Pb, element 82), polonium (Po, element 84), astatine (At, element 85), francium (Fr, element 87), radium (Ra, element 88), actinium (Ac, element 89), thorium (Th, element 90), protoactinium (Pa, element 91), uranium (U, element 92), neptunium (Np, element 93), and americium (Am, element 95).
Thus were found the mesothorium now used by physicians and manufactured industrially, radio thorium, ionium, protoactinium, radio-lead, and other substances.