Across
- 2. contains one proton and one electron
- 4. metalloid in period 3
- 6. alkali earth metal in period 4
- 8. protons in Fluorine
- 9. period 3 and group 1
Down
- 1. alkali earth metal in period 3
- 3. period 2 and group 13
- 5. group 18 and period 4
- 6. halogen in period 3t
- 7. atomic number 26