Across
- 2. negative charge
- 4. what is the atomic number of helium
- 7. J.JThomsom Atom model
- 9. what are neutrons made from
- 10. center of atom
Down
- 1. positive charge
- 3. neutral charge
- 5. what are protons made from
- 6. really tiny particle
- 8. solid energy level
