Across
- 2. - Center of an atom containing protons and neutrons (7)
- 7. - Elements typically found on the left side of the periodic table (6)
- 8. - Positively charged particles in an atom's nucleus (7)
- 10. - Essential for respiration, atomic number 8 (6)
- 11. - Halogen, used in disinfectants, atomic number 17 (8)
- 12. - Basic units of matter (5)
- 13. - Vertical groups in the periodic table (7)
- 15. - Scientist who created the first periodic table (9)
- 16. - Noble gas with atomic number 2 (6)
- 17. - Negatively charged particle found in shells around the nucleus (8)
- 18. - Basis for organic life, atomic number 6 (6)
- 20. - Alkali metal, atomic number 11 (6)
- 21. - Energy levels where electrons are found (14)
- 24. - Lightest element, atomic number 1 (8)
Down
- 1. - Another term for a vertical column in the periodic table (5)
- 3. - Pure substances consisting of only one type of atom (8)
- 4. - Atoms of the same element with different numbers of neutrons (8)
- 5. - Chart organizing all known elements by atomic number (12)
- 6. - Transition metal, atomic number 26 (4)
- 9. - Number of protons in an atom (12)
- 13. - Alkaline earth metal, important for bones, atomic number 20 (7)
- 14. - Neutral particles found in the nucleus of an atom (8)
- 19. - Scientist who proposed the model of the atom with electrons in shells (4)
- 22. - Noble gas, atomic number 10 (4)
- 23. - Horizontal lines in the periodic table (4)