Across
- 1. Layers where electrons orbit.
- 5. Negative particle outside the nucleus.
- 6. Neutral particle in the nucleus.
- 8. How easily an element reacts.
Down
- 2. Pure substance with one type of atom.
- 3. Horizontal row on the periodic table.
- 4. Positive particle in the nucleus.
- 7. Vertical column on the periodic table.