Across
- 2. middle part of atom
- 4. subatomic particle with negative charge
- 6. subatomic particle with positive charge
- 7. the smallest unit of matter
- 8. hint to know the number of valence electrons
- 9. hint to know the number of energy levels
- 10. anything that has mass and takes up space
Down
- 1. a substance that consists of atoms that all have the same number of protons
- 3. outer part of atom
- 4. layers where electrons could be found
- 5. subatomic particle with neutral charge