1. atomic number 92 a heavy toxic silvery-white radioactive metallic element
  2. atomic number 95 a radioactive transuranic metallic element
  3. atomic number 90 a soft silvery-white tetravalent radioactive metallic element; isotope 232 is used as a power source in nuclear reactors; occurs in thorite and in monazite sands
  4. atomic number 29 a ductile malleable reddish-brown corrosion-resistant diamagnetic metallic element; occurs in various minerals but is the only metal that occurs abundantly in large masses; used as an electrical and thermal conductor
  5. atomic number 96 a radioactive transuranic metallic element
  6. atomic number 52 a brittle silver-white metalloid element that is related to selenium and sulfur; it is used in alloys and as a semiconductor; occurs mainly as tellurides in ores of copper and nickel and silver and gold
  7. atomic number 94 a solid silvery grey radioactive transuranic element whose atoms can be split when bombarded with neutrons; found in minute quantities in uranium ores but is usually synthesized in nuclear reactors; 13 isotopes are known with the most important being plutonium 239
  8. atomic number 99 a radioactive transuranic element produced by bombarding plutonium with neutrons
  9. atomic number 12 a light silver-white ductile bivalent metallic element
  10. atomic number 22 a light strong grey lustrous corrosion-resistant metallic element used in strong lightweight alloys (as for airplane parts); the main sources are rutile and ilmenite
  11. atomic number 32 a brittle grey crystalline element that is a semiconducting metalloid (resembling silicon) used in transistors; occurs in germanite and argyrodite
  12. atomic number 82 a soft heavy toxic malleable metallic element
  13. atomic number 93 a radioactive transuranic metallic element
  14. atomic number 97 a radioactive transuranic element
  15. atomic number 42 a polyvalent metallic element that resembles chromium and tungsten in its properties; used to strengthen and harden steel
  16. atomic number 62 a grey lustrous metallic element of the rare earth group
  17. atomic number 72 a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons
  18. atomic number 91 a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
  19. atomic number 98 a radioactive transuranic element
  20. atomic number 9 a nonmetallic univalent element belonging to the halogens