1. atomic number 50 a silvery malleable metallic element that resists corrosion
  2. atomic number 10 a colorless odorless gaseous element that give a red glow in a vacuum tube; one of the six inert gasses; occurs in the air in small amounts
  3. atomic number 53 a nonmetallic element belonging to the halogens
  4. atomic number 54 a colorless odorless inert gaseous element occurring in the earth's atmosphere in trace amounts
  5. atomic number 58 a ductile grey metallic element of the lanthanide series
  6. atomic number 40 a lustrous grey strong metallic element resembling titanium
  7. 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
  8. 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
  9. atomic number 20 a white metallic element that burns with a brilliant light
  10. atomic number 30 a bluish-white lustrous metallic element
  11. atomic number 51 a metallic element having four allotropic forms
  12. atomic number 55 a soft silver-white ductile metallic element
  13. atomic number 56 a soft silvery metallic element of the alkali earth group
  14. atomic number 57 a white soft metallic element that tarnishes readily
  15. atomic number 59 a soft yellowish-white trivalent metallic element of the rare earth group; can be recovered from bastnasite or monazite by an ion-exchange process
  16. atomic number 60 a yellow trivalent metallic element of the rare earth group
  17. atomic number 70 a soft silvery metallic element
  18. atomic number 80 a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures
  19. atomic number 5 a trivalent metalloid element
  20. atomic number 101 a radioactive transuranic element synthesized by bombarding einsteinium with alpha particles (Md is the current symbol for mendelevium but Mv was formerly the symbol)

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