Across
- 3. positively charged center of the atom
- 4. Levels stable states of constant energy
- 7. negative electricity
- 8. the basic unit of a chemical element.
- 9. Cloud system of electrons surrounding the nucleus of an atom.
- 10. stable subatomic particle positive
Down
- 1. Electron electrons in the outermost shell
- 2. without an electric charge,
- 5. a column in the periodic table
- 6. horizontal rows of the periodic table