Across
- 5. atoms with different masses
- 6. core of atom
- 8. negative charge
- 12. top number on any element
- 13. an unstable nuclei
- 16. a positively charged ion
- 17. metallic
- 18. neutral charge
Down
- 1. mass,density,color
- 2. a property made of two elements
- 3. arrangement of electrons
- 4. positive charge
- 7. iron,neon
- 9. substance changes composition
- 10. electron shells
- 11. bottom number on any element
- 14. a negatively charged ion
- 15. basic chemical unit