Across
- 3. average mass of an element
- 5. an atom that carries an electrical charge is called an
- 6. tiny light particles that have a negative charge
- 7. number of protons
- 9. no electrical charge and located in the nucleus of an atom
- 10. large and heavy with a positive charge
Down
- 1. an electron in the outermost energy level of an atom
- 2. one less electron than proton
- 4. one more electron than proton
- 8. two atoms with different numbers of nuetrons are called