1. atomic number 49 a rare soft silvery metallic element
  2. atomic number 47 a soft white precious univalent metallic element having the highest electrical and thermal conductivity of any metal; occurs in argentite and in free form; used in coins and jewelry and tableware and photography
  3. atomic number 40 a lustrous grey strong metallic element resembling titanium
  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 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 99 a radioactive transuranic element produced by bombarding plutonium with neutrons
  7. atomic number 43 a crystalline metallic element not found in nature
  8. atomic number 89 a radioactive element of the actinide series
  9. atomic number 41 a soft grey ductile metallic element used in alloys
  10. atomic number 79 a soft yellow malleable ductile metallic element
  11. atomic number 19 a light soft silver-white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in carnallite and kainite and sylvite
  12. atomic number 39 a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys
  13. atomic number 42 a polyvalent metallic element that resembles chromium and tungsten in its properties; used to strengthen and harden steel
  14. atomic number 44 a rare polyvalent metallic element of the platinum group
  15. atomic number 45 a white hard metallic element that is one of the platinum group and is found in platinum ores; used in alloys with platinum
  16. atomic number 46 a silver-white metallic element of the platinum group that resembles platinum; occurs in some copper and nickel ores; does not tarnish at ordinary temperatures and is used (alloyed with gold) in jewelry
  17. atomic number 48 a soft bluish-white ductile malleable toxic bivalent metallic element; occurs in association with zinc ores
  18. 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
  19. atomic number 69 a soft silvery metallic element of the rare earth group
  20. atomic number 4 a light strong brittle grey toxic bivalent metallic element