1. atomic number 83 a heavy brittle diamagnetic trivalent metallic element
  2. atomic number 53 a nonmetallic element belonging to the halogens
  3. atomic number 88 an intensely radioactive metallic element that occurs in minute amounts in uranium ores
  4. atomic number 13 a silvery ductile metallic element found primarily in bauxite
  5. atomic number 43 a crystalline metallic element not found in nature
  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 73 a hard grey lustrous metallic element that is highly resistant to corrosion; occurs in niobite and fergusonite and tantalite
  9. atomic number 33 a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar
  10. atomic number 82 a soft heavy toxic malleable metallic element
  11. 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
  12. atomic number 85 a highly unstable radioactive element
  13. atomic number 93 a radioactive transuranic metallic element
  14. atomic number 23 a soft silvery white toxic metallic element used in steel alloys; it occurs in several complex minerals including carnotite and vanadinite
  15. atomic number 38 a soft silver-white or yellowish metallic element of the alkali metal group; turns yellow in air; occurs in celestite and strontianite
  16. atomic number 63 a bivalent and trivalent metallic element of the rare earth group
  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 3 a soft silver-white univalent element of the alkali metal group; the lightest metal known; occurs in several minerals

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