Scientific Crossword

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Across
  1. 4. discovered in 1898 chemical symbol
  2. 5. its atomic number is 10 it is a noble gas
  3. 6. the element under hydrogen
  4. 7. has 8 valence electrons
  5. 9. has the secound smallest atomic number
Down
  1. 1. atomic symbol is B and its atomic number is 5
  2. 2. is the very first element of the periodic table
  3. 3. has 1 valence elctron
  4. 8. horizonal on the periodic table