1. atomic number 84 a radioactive metallic element that is similar to tellurium and bismuth; occurs in uranium ores but can be produced by bombarding bismuth with neutrons in a nuclear reactor
  2. atomic number 54 a colorless odorless inert gaseous element occurring in the earth's atmosphere in trace amounts
  3. atomic number 88 an intensely radioactive metallic element that occurs in minute amounts in uranium ores
  4. atomic number 14 a tetravalent nonmetallic element
  5. 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
  6. atomic number 87 a radioactive element of the alkali-metal group discovered as a disintegration product of actinium
  7. atomic number 89 a radioactive element of the actinide series
  8. atomic number 83 a heavy brittle diamagnetic trivalent metallic element
  9. atomic number 24 a hard brittle multivalent metallic element
  10. atomic number 64 a ductile silvery-white ductile ferromagnetic trivalent metallic element of the rare earth group
  11. atomic number 74 a heavy grey-white metallic element
  12. atomic number 82 a soft heavy toxic malleable metallic element
  13. atomic number 85 a highly unstable radioactive element
  14. atomic number 34 a toxic nonmetallic element related to sulfur and tellurium
  15. atomic number 44 a rare polyvalent metallic element of the platinum group
  16. atomic number 48 a soft bluish-white ductile malleable toxic bivalent metallic element; occurs in association with zinc ores
  17. atomic number 80 a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures
  18. atomic number 81 a soft grey malleable metallic element that resembles tin but discolors on exposure to air; it is highly toxic and is used in rodent and insect poisons; occurs in zinc blende and some iron ores
  19. atomic number 86 a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health
  20. atomic number 4 a light strong brittle grey toxic bivalent metallic element

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