Across
- 4. a neutral subatomic particle in a atom
- 6. protons neutrons electrons
- 8. number number of protons
- 9. the middle of all atoms
- 10. a positive subatomic particle in a atom
Down
- 1. the basic building block of all matter
- 2. protons plus neutrons
- 3. table This table shows all the different atoms in the world
- 5. atomic mass number
- 7. a negative subatomic particle outside the atom