Across
- 2. The only gaseous element to the left of the stair step line
- 3. Columns on the periodic table
- 5. Elements found to the left of the stair step line
- 8. Positive charge in particles
- 13. Number of protons + number of neutrons
- 14. Metals founding the first group of the periodic table
- 15. Number of protons
- 16. The only metal not solid at room temperature
- 18. Atoms with the same element, but different numbers of neutrons
- 19. Elements found on the stair step line
- 20. Electrons on the outer ring of the element shell
Down
- 1. Group 18 on the periodic table, least reactive
- 4. Rows on the periodic table
- 6. The smallest part of an element
- 7. Elements found to the right of the stair step line
- 9. Positively charged center of an atom
- 10. Group 17 on the periodic table, most reactive gases
- 11. Capital letter, With or without a lowercase accompanying it
- 12. Negative charge in particles
- 17. Neutral charge in particles