Across
- 4. average mass of the naturally occurring isotopes of an element.
- 6. equal to the number of protons plus neutrons.
- 9. What is the positive charge in an atom
Down
- 1. number of protons
- 2. what are in the middle of the atom
- 3. They don't have an electrical charge
- 5. Have different atomic mass number (number of protons +neutrons)
- 7. An atom that carries an electrical charge
- 8. levels any of the possible energies an electron may have in an atom.