Across
- 4. is one of the most reactive elements in existence
- 8. is the ability of an atom to donate protons to form positive ions
- 9. soft metals that are good conductors of electricity and heat
Down
- 1. is the fast process of burning such as charcoal or natural gases
- 2. discovered neutron and its features
- 3. chemical reaction where energy is absorbed
- 5. located inside the nucleus containing a positive charge
- 6. is at the center of an atom very small and dense
- 7. tell how many orbitals does the element have