Across
- 6. = equal to the number of protrons plus neutrons
- 7. move around the outside of the nucleus and have a negative electrical charge
- 8. electrons move in definite orbits around the nucleus
- 10. = the number of protrons
Down
- 1. located in the nucleus of the atom and have a positive charge
- 2. an electron in the outermost energy level of an atom
- 3. located in the nucleus of the atom and have no electrical charge
- 4. a listing of all the known elements with their atomic masses, atomic numbers, and atomic symbols
- 5. the designer of the periodic table of elements
- 9. discovered the neutron