Across
- 3. number-atoms sum of the numbers of protons and neutrons
- 4. particle with one positive charge
- 5. solid objects that cannot be divided, created, or destroyed
- 7. a particle with negative charge
- 10. that atoms contain only one electron
- 11. decay-is a process that occurs when an unstable atomic nucleus
- 12. rows on the periodic table
- 13. Mass-is the average mass of elements isotopes
- 15. in a small area in the center of a atom
Down
- 1. elements that spontaneously emit radiation
- 2. of the same element that haves different numbers of neutrons
- 5. atoms
- 6. Table-is a chart of the elements arranged into rows and columns according to their physical and chemical properties
- 8. electrons & ray tubes
- 9. a neutral particle that exists in the nucleus of an atom
- 13. smallest piece of an elements that still represents that element
- 14. on the left side & the middle of the table