Across
- 4. protons + neutrons
- 6. inventor of periodic table
- 8. consists of protons and neutrons
- 9. positively charged particle
- 10. neutrally charged particle
Down
- 1. one or two letters than represent an element
- 2. electron in the outer shell
- 3. basic unit of a chemical element
- 5. number of protons in nucleus
- 7. negatively charged particle