Periodic Table

123456
Across
  1. 3. metals are located in the center of the periodic table
  2. 4. represents 21 % of the Earth's atmosphere
  3. 6. horizontal row on the periodic table
Down
  1. 1. tend to be good conductors of heat and electricity
  2. 2. name for elements in group 17
  3. 5. the noble gases