Across
- 3. number of protons in a neutral atom
- 6. an electron in the outermost energy level of an atom.
- 8. most reliable model
- 9. no electrical charge
- 10. An atom that carries an electrical charge
Down
- 1. equal to the number of protons plus neutrons
- 2. have a negitive electrical charge
- 4. two atoms with different numbers of neutrons
- 5. sometimes called the wave model
- 7. average mass of the naturally occurring isotopes of an element