Across
- 3. to be hammered into thin sheets
- 6. outer layers of atom made up of energy levels
- 9. anything that has mass and takes up space
- 10. positive charge, mass of 1 amu
Down
- 1. the smallest unit of matter
- 2. a substance that consists of atoms that all have the same number of protons
- 4. ability to reflect light
- 5. a substance composed of two or more elements
- 7. ability to react with other elements
- 8. center of the atom