Across
- 3. Outer layer of an atom
- 4. Vertical columns on the Periodic Table
- 5. two or more atoms bonded together
- 7. To shatter easily
- 9. Ability to reflect light
- 10. horizontal rows on the Periodic Table
- 11. Smallest unit of matter
Down
- 1. Used to identify the atom
- 2. Center of the atom
- 6. mass of 0 amu
- 8. A substance that consists of atoms that all have the same number of protons