Across
- 2. any of the possible energies an electron may have in an atom
- 3. big particles that have a positive charge
- 5. average mass of the naturally occurring isotopes of an element
- 8. an atom that carries an electrical charge
- 9. equal to the number of protons plus neutrons
- 10. big particles that have no electrical charge
Down
- 1. an electron in the outermost energy level of an atom
- 4. number of protons
- 6. how many electrons the element has
- 7. tiny particles that have a negative electrical charge