Across
- 3. the basic unit of a chemical element
- 5. positive electric charge
- 7. model of atomic structure
- 8. negative charge
- 10. the central and most important part of an object
Down
- 1. each of two or more forms of the same element
- 2. has no charge
- 4. spherical with its center as the nucleus
- 6. electrons a electron in the outermost energy
- 9. an atom or molecule with a net electric charge