Across
- 2. Negatively charged electrons repel
- 4. Emission of energy
- 7. Particle with 2 protons and 2 neutrons
- 10. Subatomic particle, negative charge
- 11. e- on outermost energy shell
- 13. Subatomic particle, positive charge
- 15. The number of neutrons and protons
- 16. [Ar]4s2 3d2
- 17. A pure substance
- 19. The number of protons in an element
- 20. Atomic number 12
Down
- 1. Row on Periodic Table
- 3. Subatomic particle, neutral charge
- 5. Same element, different AMU
- 6. Center of an atom
- 8. electron occupies lowest energy possibl
- 9. Electron number variation
- 12. Building block of matter
- 14. each electron has a unique spin
- 18. Column on periodic table