Across
- 4. another name for an atom
- 6. equal to the number of protons plus neutrons
- 8. no electrical charge
- 9. average mass of naturally occuring isotopes of an element
- 10. move around the outside of the nucleus
Down
- 1. number of protons
- 2. atom that carries an electrical charge
- 3. positive charge in the nucleus
- 5. electron in the outermost energy level of an atom
- 7. determined by number of electrons