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Periodic classification of elements -WORKSHEET-1, 1. What name was given to Dobereiner groups?State the law., 2. What is the total number of elements in Dobereiner groups, 3. How did John Newlands classify elements?, 4. Name the first element of Newland’s octaves., 5. Name the last element of Newland’s octaves., 6. What is your observation from Newland’s octaves?, 7. What is Newland’s Law of octaves?, 8. Besides atomic masses, on what other basis were the elements arranged in the Mendeleev’s, periodic table?, 9. Which chemical property of an element was treated as one of the basic properties for, classifying elements and why?, 10. What name is given to vertical columns in Mendeleev’s periodic table?, 11. What name is given to horizontal rows in Mendeleev’s periodic table?, 12. While developing the Periodic table, at few places Mendeleev inverted the sequence of some, elements i.e., he placed an element with slightly greater atomic mass before the element of, lower atomic mass. Why did he do so?, 13. Though the atomic mass of cobalt (58.9) is greater than nickel (58.7) yet Co is placed, before Ni in Mendeleev’s periodic table. Why?, 14. Which elements did not exist at the time of Mendeleev’s periodic classification? What, name was given to these elements?, 15. The three elements predicted by Mendeleev from the gaps in his periodic table were known as, eka- boron, eka- aluminum, eka- silicon. What names were given to these elements when they, were discovered later on?