Periodic table

Edit Answers
123456
Across
  1. 2. the second lightest atom
  2. 4. an atom with 18 protons and 18 electrons
  3. 6. an atom with the melting point of -248C
Down
  1. 1. atom with the 131.3 as it's atomic mass
  2. 3. number 36 in the periodic table
  3. 5. first found in 1900