Across
- 3. smallest piece of an element
- 5. atomic particle with negative charge
- 6. describes elements that spontaneously emit ration
- 7. average mass of an elements isotopes
- 11. neutral particle in the nucleus of an atom
- 12. small area in the center of an atoms mass
- 13. the number of protons in a atom
Down
- 1. proces that occurs when unstable atomic nueclus changes into another
- 2. occuring without external force or cause
- 4. sum number of protons and nuetrons in an atom
- 5. area around an atomic nucleus
- 8. atomic particle with positive charge
- 9. any two or more atoms same element that has different number of nutrons
- 10. an atom that is no longer neutral because it gained or lost charge