Across
- 2. Fe
- 3. neutrally charged subatomic particle
- 8. describes outermost shell/electrons
- 9. He
- 12. negative ion
- 15. centre of an atom
- 17. 4 or less electrons
- 18. an atom with a different number of neutrons
- 19. when an atom has a full outer shell
Down
- 1. positive ion
- 4. the smallest of the three subatomic particles
- 5. maximum number of electrons in first shell
- 6. 5 or more electrons
- 7. positively charged subatomic particle
- 10. protons plus neutrons
- 11. atom with an imbalance of protons and electrons
- 13. columns of a periodic table
- 14. rows of a periodic table
- 16. maximum number of electrons in second and third shell