modern periodic table

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Across
  1. 4. the elements in group zero are called
  2. 8. group 17 elements are
  3. 9. classification was based on
  4. 10. the first element of rare earth metal is
  5. 11. vertical rows in periodic table is known as
Down
  1. 1. first nobal gas in table
  2. 2. modern periodic table is discovered by
  3. 3. metal which is most reactive
  4. 5. the first alkali metal is
  5. 6. the no. Of e- in the valence shell is equal to its
  6. 7. family of element to which potassium belongs to
  7. 12. horizontal rows in periodic table is known as