Across
- 1. part of the atom that is positively charged
- 4. ____ number tells us how many protons and neutrons are in the nucleus
- 5. a beta particle has this charge
- 10. radioactive particle that is a fast moving electron
- 11. radioactive particle that is made of two protons and two neutrons
- 12. ____ number tells us how many protons an atom has
- 13. JJ ____ discovered electrons
- 14. an alpha particle has this charge
Down
- 2. discovered the nucleus
- 3. type of radiation that is a wave
- 5. the neutral part of an atom
- 6. part of the atom that is small and negatively charged
- 7. the time taken for half of the radioactive atoms to decay
- 8. James _____ discovered neutrons in the nucleus
- 9. John ____ scientist who said everything is made out of atoms