Across
- 1. the number of protons plus the number of neutrons in an atoms nucleus
- 9. the force of attraction and repulsion between electrically charged particles
- 11. negatively charged subatomic particles
- 14. particles smaller than an atom
- 16. the number of protons in the nucleus of an atom
Down
- 2. the unit of mass used to describe atoms
- 3. the rings of the Bohr model correspond to different _________ levels
- 4. the center of an atom
- 5. the force of attraction between all objects that have mass
- 6. atoms of the same element that have different number of neutrons
- 7. the force that controls radioactive decay
- 8. the average mass of all isotopes of an element
- 10. where electrons reside outside the nucleus of an atom
- 12. subatomic particles with no electric charge
- 13. the force that binds the protons and neutrons together in the nucleus
- 15. the particles that make up protons and neutrons