Across
- 1. The total number of protons and neutrons in an atom
- 7. Pure substance made of only one kind of atom
- 8. A group of atoms bonded together
- 9. The science that studies matter and its changes
- 10. Positively charged particle in an atom’s nucleus
Down
- 2. The number of protons in an atom
- 3. Particle with no electric charge
- 4. The central part of an atom
- 5. Basic unit of a chemical element
- 6. Negatively charged particle orbiting the nucleus