Across
- 1. metal+metal
- 3. positively charged particle
- 6. tiny piece of everything
- 7. in the middle of an atom
- 8. has the same number of protons
- 9. a charged atom
- 10. number of protons of an atom
- 11. a unit of mass that describes the mass of an atom or molecule
- 12. zero charged particle
- 14. negatively charged particle
- 15. around the nucleus
- 17. holds quarks together
- 18. the number of groups in the Periodic Table
Down
- 2. the mass of an atom expressed in atomic mass units
- 4. the sum of the numbers of protons and neutrons in the nucleus of an atom
- 5. created the Periodic Table
- 9. metal+non-metal
- 11. makes up everything in the universe
- 13. an atom
- 16. non-metal+non-metal