Across
- 1. path an electron travels around the nucleus
- 3. small, dense, central part of an atom
- 5. discovered the neutron
- 9. has mass and volume
- 10. discovered charge and mass of an electron
- 12. the "DNA" of an atom
- 14. discovered the nucleus of an atom
- 15. same atomic number but different neutrons
- 17. sum of protons and neutrons
- 19. said all matter was made of atoms that were indivisible and could form compounds
- 21. discovered the electron from cathode rays
Down
- 2. an atom that has gained or lost an electron
- 4. negative particle found outside the nucleus
- 6. tells the number of protons in an atom
- 7. due to a loss or gain of electrons
- 8. "atomos"
- 11. weighted average of all an atom's isotopes' masses
- 13. particle responsible for isotopes
- 16. atomic model with electrons embedded in a positive atom
- 18. basic unit of an element
- 20. described the atom like a solar system