Across
- 3. English physicist who justified physical laws
- 4. Danish physicist received Noble Prize in physics
- 5. father of nuclear physics
- 7. electrons go around the nucleus of an atom
- 9. element that is shiny
- 13. ion that has a positive charge
- 14. sum of number of protons and neutrons
- 15. number number of protons in the nucleus
- 16. subatomic particle with no charge
- 17. English physicist discovered the neutron
- 20. British scientist showed cathode rays
- 21. English chemist
Down
- 1. an ion that has a negative charge
- 2. Greek philosopher formulated atomic theory
- 6. cannot be separated
- 7. a substance that cannot be broken down
- 8. element that conducts heat
- 10. negatively charged subatomic particle
- 11. positively charged central region of an atom
- 12. subatomic particle with positive charge
- 14. anything that has mass and takes up space
- 18. an atom that has same number of protons
- 19. an atom or molecule
- 22. smallest unit of an element