Across
- 2. **** number; the total number of protons and neutrons
- 3. smallest unit of matter
- 6. a substance consisting of 2+ different elements
- 7. the tendency of an atom to attract electrons
- 8. anything that has mass and occupies space
- 9. ******* shell; the outermost electron shell
- 10. ****** number; the number of protons unique to that element
- 11. capacity to cause change
Down
- 1. different atomic forms of the same element
- 4. an atom (or group of atoms) that has gained or lost electron/s
- 5. a chemical that is not reactive; the valence shell is full
- 7. substance that cannot be broken down
- 8. a substance consisting of 2+bonded atoms