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PERIODIC TABLE |
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1.When did Mendeleev create the periodic table? 2.Why was Mendeleev's periodic table better than the others in the time? 3.What is radiation? 4.What's the difference between radiation and radioactivity? 5.What are the name of the seven main groups of the Periodic Table? 6.What is the last valence shell of the following groups?:Halogens ,Noble Gases, Alkali metal and Alkaline earth metal. 7.Tell if the following sentences are true or false. -Thallium has an hexagonal crystal structure -Chlorine has an electronegative of 3'17 8.What are the names of the first and fourtheen group? 9.What are isotopes? |
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