2. The Periodic Table of Elements

7. History Check 1649-1 st scientific discovery of an element by Hennig Brand(the German alchemist treated urine to a series of processes that resulted in the production of phosphorus)

11. 32 Ge Germanium 72.63

12. 39 Y Yttrium 88.905

13. 43 Tc Technetiu m (97.9072) 44 Ru Ruthenium 101.07 45 Rh Rhodium 102.905 46 Pd Palladium 106.42 47 Ag Silver 107.868 48 Cd Cadmium 112.411 49 In Indium 114.818

14. 52 Te Tellurium 128.06

15. History Check 1869-63 elements have been discovered

16. 59 Pr Praseodymium 140.90 61 Pm Promethium (145)

17. 62 Sm Samarium 150.36 64 Gd Gadolinium 157.25

18. 67 Ho Holmium 164.93 70 Yb Ytterbium 173.05 76 Os Osmium 190.23

20. 81 Ti Thallium 204.38 83 Bi Bismuth 208.98 85 At Astatine (209.98)

21. 88 Ra Radium (226)

22. History Check Glenn Seaburg made last major changes to periodic table in middle of 20 th century starting with the discovery of plutonium in 1940(finished the transuranic elements 94-102)

23. 92 U Uranium 238.02 94 Pu Plutonium (244)

24. 96 Cm Curium (247) 99 Es Einsteinium (252)

25. History Check Lothar Meyer and Dmitri Mendeleev 1 st produced and published remarkably similar versions of the periodic table. Dmitri was known as “Father” of the Periodic Table of eEements.